"This book is dedicated to the memory of Michael Marinov, the theorist who together with Felix Berezin introduced the classical description of spin by anticommuting Grassmann variables. The Volume contains original papers and reviews of physicists and mathematicians written specifically for this book. These articles reflect the current status and recent developments in the areas of Marinov's research interests: quantum tunneling, quantization of constrained systems, supersymmetry and others. Included personal recollections portray a human face of Michael Marinov, a person of great knowledge and integrity."--BOOK JACKET.