This is a major revision of a classic, best selling reference book. Originally published by the American Institute of Physics under the title "Physics Vade Mecum" in 1981, and then the second edition in 1989 with the new title "A Physicist's Desk Reference", this third edition has been completely updated and modernized to reflect current modern physics. The book is a concise compilation of the most frequently used physics data and formulae with their derivations. This revision has six more chapters than the second edition, outdated chapters dropped, and new chapters added on atmospheric physics, electricity and magnetism, elementary particle physics, fluid dynamics, geophysics, nonlinear physics, particle accelerators, polymer physics, and quantum theory. There is a new last chapter on practical laboratory data. The references and bibliographies have been updated. This book is an indispensable tool for the researcher, professional and student in physics as well as other scientists who use physics data. The editors of this volume are Richard Cohen, author of the first two chapters of PDR and the "Physics Quick Reference Guide"; David Lide, one of the editors of the previous two editions and the editor of the "CRC Handbook of Physics and Chemistry"; and George Trigg, editor of the "Encyclopedia of Physics" and the "Encyclopedia of Applied Physics" (VCH). The market for this classic reference book includes the practicing scientist, including engineers, chemists, and biologists; and students.