Electrocrystallization is a particular case of a first order phase transition and Electrocrystallization is a particular case of electrochemical kinetics are two statements that I have heard and read many times. I do not like them for a simple reason: it is annoying to see that the subject to which you have devoted more than 30 years of your life may be considered as a particular case. Therefore, I decided to write this book in which Electrocrystallization is the main subject. To become competent in the field of Electrocrystallization one should possess knowledge of Electrochemistry, Nucleation and Crystal Growth, which means knowledge of Physical Chemistry, Physics and Mathematics. That is certainly difficult and in most cases those who study Electrocrystallization are either more electrochemists, or more physical chemists, or more physicists, very often depending on whom has been their teacher. Of course, there are scientists who consider themselves equally good in all those fields. Very frequently they are, unfortunately, equally bad. The difference is essential but strange enough, it is sometimes not easy to realize the truth immediately.