This book will be a non-technical book on string instruments that includes some technical information as well. The emphasis will be on the practical understanding of string instruments, with the interests of performers and instrument builders in the forefront. Authors of the chapters will be musicians, scientists, and instrument designers and builders with practical experience. The mathematics will be kept as simple as possible by translating ideas from the language of physics (mathematics) to non-mathematical language. Considerable emphasis will be placed on the design and construction of string instruments. Following the structure of the author's successful Science of Percussion Instruments (World Scientific, 2000), technical ideas will be presented as "interludes." Readers who wish to go beyond the simple ideas in this book can easily follow the references to more scientific books and to the original scientific literature.