The present study is groundbreaking for Greek data and especially for Greek legal science. This is because it manages to connect the findings of the science of behavioral economics with the regulatory field, which is primarily the responsibility of legal science. This project specifically concerns the practically significant area of the capital market, the meeting of which with behavioral economics has long given birth to the particular branch of behavioral finance. This work attempts, on the one hand, to highlight the shortcomings of the existing regulatory framework for the capital market, to the extent that it fails to adequately protect the interests of investors due to the non-consideration of basic investment errors or behavioral weaknesses, and on the other hand, within the framework of a spirit of mild paternalism, to suggest the mildest possible regulatory interventions to improve this framework. Thus, the book is important and useful not only for those who are practically and theoretically involved in the field of the capital market, but also for those who exercise public or regulatory policy in this field.

With this book, the reader has the opportunity to explore the world of the capital market and the basic irrational behaviors or phenomena observed in it. Often, for example, investors mistakenly assume that the previously rising price of a stock predicts its further upward movement in the future, as happened in the United States during the periods preceding the Great Crash of 1929 or the collapse of the prices of "new economy" stocks in the early 2000s, periods during which the frenzied rise in stock prices created an irrational exuberance in investors, making them believe that stock prices would rise endlessly. And all this at a time when, according to the - rational - assumption of efficient capital markets, "the already realized prices do not contain any indication or information about the movement of future prices, which could be used by traders to make profits that exceed the returns from simple holding of securities" (related to Thomadakis/Xanthakis, Money & Capital Markets, p. 196). From a broader perspective, this book is part of a new, wider legal methodological trend, that of the behavioral economic analysis of law.

The new concept, although it uses some of the tools of traditional economic analysis of law, distances itself from the basic starting point of the latter, from the model of societies as perfectly rational thinking and acting subjects (rational choice theory), and adheres to the - ontologically more accurate - theory of bounded rationality, according to which in our everyday activity we often act wrongly-irrationally, that is, we make decisions that ultimately do not maximize our benefits.

The strong penetration of behavioral economic analysis of law into decision-making centers in the United States - as well as in EU member states such as the United Kingdom and Germany - and its transformation into a tool for shaping and implementing public policy, especially for the protection of investors, consumers or other vulnerable social groups, is due, among other things, to the fact that taking into account the behavioral dimension in the establishment and application of legal rules is considered to be able to significantly contribute to the efforts of the US authorities to prevent the recurrence of the financial crisis of 2008 and especially the traumatic experience of the collapse of the real estate market (due to the infamous subprime lending).

At the same time, however, behavioral economic analysis of law has infiltrated various other areas of shaping and implementing public policy, such as the design of efficient social security or pension programs, the protection of health and the environment, the conservation of public resources, etc.

Taking into account the findings of behavioral research and experiments, especially in the formulation of investor protection law, primarily means placing existing regulations under the burden of empirically established reality regarding the behavior of investors and, subsequently, formulating proposals for alternative regulations that could better meet the stated goals and emerging needs. The expansion of the perspective of EU legislation (e.g. Directive 2014/65/EU, MiFID II) as well as national legislation in this direction presents as its main advantage the fact that legal rules that are amended after studying the actual behavior of societies, rather than based solely on theoretical models or assumptions, are more likely to achieve the main purpose, namely the effective protection of the investor. And this becomes evident through the pages of this book.

Within this framework, the general importance that the specific architecture of each custodial intervention of the legislator has for the law is also highlighted, even more so the nature of the law not only as a science of interpretation and application of positive law but also as a science of adjudication or correct legislation, which investigates to what extent the legislator can even achieve a specific regulatory purpose using a specific regulatory tool or, consequently, what undesirable side effects it should accept when using this tool, especially now, mostly, in light of the newer assumptions of behavioral economic analysis of law.