Book excerpt: Susceptibility Tensors for Nonlinear Optics is a unique and invaluable reference book with accompanying software. Starting from basic principles, the book presents a detailed introduction to the concept of optical susceptibilities of crystalline media. Substantial appendices include useful tables of third-, fourth-, and fifth-rank susceptibility tensors for major nonlinear optical effects. Integral to the book is an entirely original TURBO RANK software package (compatible with PCs running MS-DOS and Windows) that allows the calculation of the symmetry of material tensors up to seventh rank, effectively superseding conventional reference tables of high rank tensors. This package is also useful for scientists working in solid state physics, crystallography, acoustics, and materials engineering.