A standard elementary and intermediate text for persons seriously interested in modern scientific methods for enciphering and deciphering cryptograms. It does not simply repeat older material, but contains much about modern cryptanalysis that is not generally known except to experts. It is especially strong in modern forms of cipher solution. This clear and thorough text also provides you with 166 specimen codes to solve. This edition for the first time also includes solutions. A special appendix includes final letters, sequence charts, digram, trigram tables, most common words in English and frequencies in English. German. French, Italian, Spanish and Portuguese.