The provided text is the table of contents and preface for the third revised edition of the "Handbook of Nonlinear Optical Crystals" by V. G. Dmitriev, G. G. Gurzadyan, and D. N. Nikogosyan. The handbook is part of the Springer Series in Optical Sciences and is edited by A. E. Siegman. It covers the properties and applications of nonlinear optical crystals, including detailed descriptions of various crystals, their optical properties, and their use in laser frequency conversion, harmonic generation, sum-frequency generation, difference-frequency generation, and optical parametric oscillation. The preface highlights the rapid developments in nonlinear optical crystals and laser techniques that prompted the revision of the second edition, with significant updates in the third edition. The book is intended for specialists and practitioners in the field of nonlinear optics and laser physics.The provided text is the table of contents and preface for the third revised edition of the "Handbook of Nonlinear Optical Crystals" by V. G. Dmitriev, G. G. Gurzadyan, and D. N. Nikogosyan. The handbook is part of the Springer Series in Optical Sciences and is edited by A. E. Siegman. It covers the properties and applications of nonlinear optical crystals, including detailed descriptions of various crystals, their optical properties, and their use in laser frequency conversion, harmonic generation, sum-frequency generation, difference-frequency generation, and optical parametric oscillation. The preface highlights the rapid developments in nonlinear optical crystals and laser techniques that prompted the revision of the second edition, with significant updates in the third edition. The book is intended for specialists and practitioners in the field of nonlinear optics and laser physics.