Reviews

Secret codes capture the interest of children as well as adults, and this book takes a wonderful approach to exploring codes as they were used from ancient times to their use in today's world. Although the text is easy to read at a third- or fourth-grade reading level and concisely presents information on different types of codes - including Navajo code talkers and Cockney rhyming slangs - its content is appropriate for higher elementary and middle school grades as well. Explanations are clear, so the student reader needs a minimal amount of adult assistance to fully benefit from the book's content. One of the book's major strengths is the frequent invitation for the reader to decode and encode using the different codes described. The decoded answers can be found at the end of the book. Readers are encouraged to try writing messages using the different codes. Another of the book's strengths is the connections it makes to major historical events. Explanations are presented regarding the codes used by Julius Caesar, Kepler, Galileo, Leonardo da Vinci, and Thomas Jefferson, to name a few. In addition to the explanations, the author includes justification for the use of codes during each period of history. Making Secret Codes has no storyline; nevertheless, the author manages to smoothly transition from one cryptographic strategy to the next. The book includes a table of contents, an index, a comprehensive glossary, and both text and Internet resources for further exploration of codes.-- "Teaching Children Mathematics, National Council of Teachers of Mathematics"