Those who delight in puzzles can find much to ponder here 8212 Science News LetterWill be well received by anyone really interested in the subject 8212 Scientific Book Club ReviewReaders interested in secret writing will find this book an excellent elementary explanation of transposition and substitution ciphers, codes, and their solutions More than 150 problems provide practical application as well as tests of skill and ingenuity After a brief description of the history of secret writing, the reader is introduced to fundamental principles of ciphers 8212 transposition and substitution 8212 and given an understanding of the various methods of enciphering and deciphering secret messages The author covers geometrical patterns, route transcription, columnar transposition, and other methods used in transposition under substitution, he treats mixed cipher systems, singlealphabet and polyalphabetical substitution, mechanical devices, the Vigen232re system, etc A discussion of cryptanalysis leads the reader into 151 problems for which answers are provided at the end Appendixes offer notes on enciphering Japanese and explanation of the Baconian Biliteral Cipher frequency tables for English, French, German, Italian, and Spanish