Excellent and very informative. . . Many well selected examples are discussed which guide a new researcher into the field. It is also a fantastic source of historical, fundamental and up to date papers and reviews (110 pages of references). This book then can be read by a beginner in the field but also by an active researcher in polymorphism, crystal engineering or crystal chemistry. * Claude Lecomte, Acta Crystallographica, February 2021 * Joel Bernstein's book represents the single most important source for the development of critical understanding of polymorphism and its commercial and industrial importance and might well play a decisive role in categorizing and reorganizing problems and endeavours on polymorphism-related research. * Current Engineering Practice * Clear, vigorous, well-written and very readable ... There seems to be nothing relevant that Bernstein has not included; his scholarship and command and study of the vast literature are remarkable ... an excellent work. * Current Engineering Practice * An excellent resource book and a very good read ... can be recommended strongly both for content and interest. * Crystallographic Newsletter * A delight to review this eagerly awaited tome ... In the end, the proof of the pudding is in the eating, and in my opinion, Bernstein has served us a nutritional feast here. Enjoy! * Cryst. Growth Des. * It will be the book, for a long time to come, to which students and researchers will turn with confidence, as well as pleasure, in all questions of polymorphism in molecular crystals. * Structural Chemistry *