The desire to solve mysteries is as old as humanity and the spell of an unknown writing has always been particularly potent. This is a discussion of the contributions to the science of decipherment made by theorists such as Leibnitz and by brilliant practitioners of it from Champollion to Ventris. Maurice Pope examines the intellectual developments that lead to their outstanding achievements, and describes the process of decipherment, providing quotations from their original publications and many examples of their drawings, tables and diagrams. Among the scripts the author analyses are the Palmyra script, Sassanid Persian, Egyptian hieroglyphic, Persian cuniform, Akkadian cuneiform, the Cypriot syllabary, Hittitte hieroglyphic, the Ugaritic alphabet and Mycenaean Linear B.