A review of various legal rules comprising the law of obligations in the Iranian legal system demonstrates that this system recognizes a special type of obligations with the unusual property that its burden is neither on one specific person (individual responsibility), nor on several persons simultaneously (joint responsibility), but, in two or more subsequent stages, along a specified priority, on different persons, so that in each stage, the creditor's claim is due to be paid from a different person’s property. The creditor could pass to the next stage only when in the previous, there has been found no, or insufficient, assets. The obligations of involved persons, in other words, cover each other alternatively. The type of obligation thus described has not been viewed as a genuine, independent one in the Iranian legal system so far. Rather, it is considered as a special and exceptional phenomenon, or even as an irregularity. Therefore, the instances fitting in this type have not been collected and studied together, its constituting elements have not been specifically studied, and the rules governing it have not been formulated. This article is intended to study this type of responsibility as a genuine and independent type among obligations and to examine its instances, elements and the rules governing it. The method of this research is descriptive and analytical. Accordingly, in the beginning, the article will descriptively review various laws that contain, or constitute an application of, the sequential responsibility, either explicitly or implicitly. Then, in the analytical phase, an attempt will be made to derive the general principles, elements and rules governing the provisions embodied in that particular body of law. In this way, the most important interpretive instrument will be the induction from various legal provisions. The library research method will also be employed. The hypothesis of this research is that the sequential responsibility is not exceptional or irregular, but a genuine, purposeful and regular type which the legislator is able to use when necessary. It is a combination of the individual and the joint responsibility, aiming to support both the debtor and the creditor at the same time. Also, it can be conceived as a form of insurance for a number of obligations, each backed by the obligation(s) of the next stage. Therefore, by coherent explanation and analysis of the rules governing this type of responsibility, the scope of its appropriate application can be suggested to the legislator and to the legal doctrine. The principal questions of this research are: 1. what are the examples of sequential responsibility in the Iranian laws? 2. What are the structural characteristics and the elements of this type and its differences with other types of responsibility? 3. What general rules governing this type could be induced and to what issues could they be applied? On the other hand, the following hypotheses will be suggested: 1. The hierarchy between the liabilities of different persons for paying alimony to relatives, as well as the sequence in paying the blood money between a) Aqila (paternal relative of the felon), b) the felon, and c) the public treasury are prime examples of this type of responsibility. Also, the sequence between a) minor's liability and b) its culpable guardian's liability, and in some cases, the liabilities of a) the company director and shareholders/members, and b) the company/legal entity should be considered as examples of this type of liability, 2. The elements of this type of responsibility are: sequentiality, single debt, and multiple properties. 3. There are general rules governing matters such as: the aim of responsibility, the relationship between liable persons, and the scope of responsibility. This article has depicted as a regular category a group of obligations that have always been viewed as sporadic or exceptional cases. The article will present them as an independent, original institution in the Iranian law, with the proposed name "sequential liability". Various instances of this type of liability will be traced through different laws and put together as a coherent category. These include: sequential liability between the invalid (the insane and the minors) and their culpable guardian (Article 7 of the Civil Liability Act), sequential responsibility between different persons for paying alimony to their relatives (Articles 1198 et seq. of the Civil Code), sequential responsibility between the director of a legal entity and the entity itself to compensate for damages caused by a crime (Article 28 of the Protection of Authors, Writers and Artists Act, legislated in 1970), sequential liability between limited liability and general partnership companies and their partners/shareholders (Articles 126, 186 and 187 of the Commercial Code), sequential liability between the company and its culpable director against third parties (Article 143 of the Amendment to the Commercial Code), and sequential responsibility between the Aqila (paternal relative of the felon), the felon, and the public treasury, to pay blood money (Articles 470, 435, 471, 474 and 475 of the Islamic Penal Code). Instead of focusing on divergences, the article will explore similarities and common elements in various cases, as is necessary in any scientific research. Common elements are: a) sequentiality, which means the sequential relation between a number of obligations based on a specified priority, b) multiple properties, meaning that sequential responsibility shifts, at each level, from one liable person’s property, to the property of the person in the next rank, c) one debt, meaning that the content of obligation is the same for all sequential ranks, bearing same qualitative and quantitative characteristics. Finally, by induction from various bodies of law, and by taking into account the purpose and the rationale behind this type of responsibility, the general rules governing it, which are applicable in similar cases or when no specific rule can be found in the texts, will be formulated as follows: first, the aim of sequential liability is to support both the creditor and the debtor, in that the creditor will have access to multiple properties to collect the debt, and the debtor will not be forced to face hardship by fulfilling the debt. Thus, this is a genuine category of responsibilities, along with the individual and the joint responsibility, second, as to the relationship between sequential debtors, since each of them is paying his own debt, he cannot, in principle, claim against those in the previous or the next rank to refund what he has paid, such as is the case for the one who pays the relative’s alimony, third, the scope of sequential responsibility, in accordance with its rationale and its premises, is that each debtor in any rank is responsible for all of the debt, and only the portion he failed to pay will be transferred to the next rank. As for the case where several debtors are in the same rank, the rule is that each will have to pay an equal share of the debt.

It is the law which must provide the suitable and efficient tools to execute the legal rules some constitutions as mortgage, guarantee, joint and several liability and imprisonment of the debtors are created for this main. The insolidum liability constitution as far as others facilitates somehow the execution of the legal rules. Insolidum liability is a kind of joint and several liabilities, It means that the creditor can refers to each one of the debtors for the whole debt. But it is different from joint and several liability, because in the first place, the secondary effects do not exist in the Insolidum liability, and in the second place by absence of relation in the responsible, the payer can not refer to the others to compensate the payment out of his portion. This constitution is not acquainted in our legal system but there are some cases of plurality of responsible which correspond with this constitution.

Defense based on civil liability is divided into different categories based on its multiple meanings and diverse functions. One of the important types of defense in civil liability is the defense based on limiting the amount of responsibility, the proof of which without negating the responsibility of the defendant, simply reduces the scope of the defendant's responsibility and the amount of damages payable by him. Despite the importance of defenses based on the limitation of liability in harmonizing the rules of civil liability in terms of compensation and also creating a favorable legal order in civil liability claims, the examination of this type of defense as an independent topic in our legal system has been neglected. The current research, with descriptive analytical methods and with the approach of emphasizing the civil responsibility of the police, seeks to provide a coherent basis for the classification of defense types based on the limitation of responsibility in civil liability lawsuits through a systematic interpretation of domestic laws. In this regard, three general categories of defenses based on liability limitation in civil liability lawsuits can be identified and examined that are respectively based on the defense based on role of the victim in connection with the accident (including the contributory negligence of the victim and also the breach of the duty to mitigate damages), the defense based on intervention of third parties and Multiple Tortfeasors in the occurrence of the accident and in the end, the defense based on good faith of the Tortfeasor is divided.

Despite the fact that in investigations and legal writings enough consideration has been paid to the founding principles and rules governing civil and criminal liability as well as damages of crime, the legal or disciplinary responsibility accompanying these two types of legal responsibilities has not been taken seriously into account and the people involved it-in particular, the authorities dealing with violations of law and order-remain in this fundamental ambiguity: in the proceedings, as well as in the definitions and identifying the scope of the relevant judgments, should they follow the criminal or civil responsibilities? If we try to clarify and solve some important issues such as the fundamentals of identifying violation, the factors of evading legal responsibility, the role of the spiritual element in the occurrence of the violation, as well as other rules and principles of law enforcement in legal investigations, we can help the authorities who investigate the violations to take a right direction. Accordingly, in this paper, while presenting a definition of legal responsibilities, we describe the fundamental differences of civil and criminal liability with law enforcement, and finally we prove the third part of the responsibility under the title of law enforcement with its own rules and regulations

Although transactions are complicated and of specific variety nowadays, concern of both parties of transactions concerning probability of deservingness of each considerations is so important that all legal schools have thought about some solutions for removing that concern and creating peace of mind for both parties. Islamic legal law has not ignored that important issue too, and has offered liability of darak for solving such a problem. In addition to clarifying the concept of liability of darak, the present research attempts to nullify the opinion which claims its synonymy with that of ‘uhda through correct explanation of the essentials and conditions of its actualization, and to remove its exclusiveness to the contract of sale through expanding it to other exchanging contracts. 

Because police work involves risky split-second deisions, officers become subject to a wide range of investigations, complaints, and legal against them When police fail to  perform them negligently, or abuse their authority ,the possibility of civil liability exists. Police may be responsible in the following cases: civil liability for police use of excessive force. police civil liability for failure to protect, police civil liability for negligent pursuits, police civil liability for failure to arrest intoxicated drivers ,police civil liability for failure to prevent detainee shicide and the liability of traffic officers. We have defind in the article legal foundations for police civil liability and exemptions.

Since a clear criterion has not been mentioned for liability in religious scriptures and as a result jurisprudents and those who have written the law have only mentioned some instances of liability, problems have occurred for the courts of law. This article has been written to address the necessity of introducing a criterion to be referred to in cases that are unclear and are not mentioned in scriptures. The outcome of this study is that the criterion for liability is the one whom the crime is referred to not other criteria such as aggressive nature of the act or negligence of the perpetrator. Based on this, to consider someone liable it suffices the loss and harm be referred to him/her; whether the act has been aggressive or not and whether the perpetrator has been negligent or not. Relying upon this rule, when there are a number of causes liability should be attributed to someone whom the crime is referred to by the common sense. If the loss and harm are referred to more than one source by the common sense then each one will be liable proportionately.

In the history of the law of torts, there is damages arising out of things. Some of these damages are because of things’ actions, such as buildings collapses, animals' behaviors, and cars accidents and so on. At the first, who have liability for the victim’ s injuries and damages are the proprietor and possessors; but in pursuit of technical developments of the era, we shouldn’ t ignore liability of producers and designers of these products. We all know that the technological progress of humankind is the cause of unbelievable innovations. One of this human incredible ingenuity is making of object acting similar to mankinds. For example, it can be a human-assisted robot, such as cleaning and cooking, or specializing in medicine, and the like. So there is a legal problem asking about legal situations of these creations. Now, the smart object may not be a common issue in the community, but events show that we will have to confront with difficult issues in the near future. So, today we need to think about its legal dimensions and solve the problems arising from the personality, ownership, contract and responsibility of these digital age objects. Moreover, studying the emerging institutions sheds light on current issues in the light of which we can illuminate the dim dimensions of many current and traditional problems and illustrate the ways we have gone wrong. The objects that are armed with a will, can have ownership on others objects and conclude a contract with persons and may harm others, either voluntarily or by the will of people realized in the object. For example, active home-based artificial intelligence can provide harm to guests or surgery or treatment robots can harm patients, or a driverless car may cause harms to pedestrian and create financial losses with accidents. If the basis of liability is fault, the owner of the objects would be liable as much as it was at fault. A master is someone who has effective supervision or guidance on an object at the time of the crash, such as a car driver. In Iranian law, the responsibility of the owner is based on fault, whether living, inanimate, movable or immovable property. In addition to the owner and possessor, sometimes the creator and designer of the object is responsible for the caused damage. With all of the foregoing, we may still be considering new and separate AI. But first, we need to know that AI has three features: it understands the world, analyzes the information received, and then acts on it. Machines are planned elsewhere and do not have means to act in the sense of freedom of the human will; now, is it right to hold them responsible? Today, it appears that there is less of a means to perceive, think and act independently. In fact, most machines are not independent and cannot think and decide. The object may be autonomous in performing certain tasks, so people associated with the object, such as the artificial intelligence manager or the author of the program and its software, will be responsible for compensating for the resulting damage. Apart from that, we may have a personality for artificial intelligence and recognize him or her as a right-doer; in this case, in addition to being a person's representative and subject to responsibility, the robot may be itself responsible for its actions. In this situation, the robot knows the true meaning of 'act' and truly is realized. The machine has many different types of autonomy and power. Some tools are human instrument and others have the power to act. Among the latter category, some may be in control of their affairs, and some are still involved in the determinacy of algorithms. Artificial intelligence is the criterion of selfresponsibility, that is, the robot is able to manage its financial affairs. In that case, civil liability can be borne. Otherwise, the person is responsible for its actions and if it is damaged by a third party, the person responsible may be the owner or the developer or the creator. Given the fact that there is still theoretically independent of the robots, it is necessary in the present circumstances to consider it a tool and hold others responsible for its actions. However, the legislator is supposed to prescribe rules on the personality and responsibility of artificial intelligence, and this is impossible unless the unknown dimensions of the presence of these electronic persons in society have been explored by lawyers.