Today, most developing countries have reached middle-or high-income levels, and their material infrastructure and equipment are similar to, or even competitive with, those of developed countries in many ways. However, conscious people living in these countries understand that some behaviours paralyse the economic, political and social systems of their countries, and they experience the difficulty of conceptualising these behaviours, the number of which is in the hundreds, relating them to current performance, and not being able to consider them as a whole. More than a hundred behavioural patterns discussed in this book with in the scope of behavioural underdevelopment seem to have the potential to meet this need, at least partially. The main purpose of this book is to try to shed light on this subject at a universal level. For this purpose, with the new subchapters added to the first original Turkish edition of the book, the probability of occurrence of each defined behaviour in other developing countries and, in developed countries, has been tried to be revealed within the framework of a holistic comparative probability analysis.