This is the most up-to-date book on solitons and is divided into two parts. Part 1: Detailed introductory lectures on different aspects of solitons plus lectures on the mathematical aspects on this subject. Part 2: Is a collection of reprints on mathematical theories of solitons, solitons in field theory, solitons as particles and their properties, especially topological and physical properties. This book is aimed at a wide audience of physicists and mathematicians. It is an ideal reference book for young researchers and graduate students.