Sol-Gel chemistry roots are quite ancient but Sol-Gel really appears as a self-standing field of science and technology in the late 70’s. In 1981, the first international conference was held in Padova chaired by late Professor Gottardi and the International Sol-Gel society was launched in 2003. Now Sol-Gel is widely recognized as an important field of science and is spreading far beyond the initial circle of materials chemists. This success of Sol-Gel chemistry exemplified by the development of the field of Hybrid materials, is linking communities together, from physics to biology, from polymers to biomaterials and many others. Some 40 years after the birth of Sol-Gel science, this book is proposing to look back at some basics of the field in a very timely manner. It is always nice from time to time to go back to more fundamental issues since as mentioned by the author “the current trend in materials science is more focusing on applications and fewer studies are devoted to understanding the basic science behind “. Prof. Innocenzi (University of Sassari, Italy) is not only a famous and respected scientist in the field but also a fantastic storyteller, this gives this book a peculiar style and multiplies the pleasure of reading. Throughout the six chapters of this book, we travel along the Sol to Gel Transition in a very concise but detailed way for the pleasure and benefit of the readers. No doubt that this book was necessary and will serve to better educate the young scientists entering the field.