I believe I read this book in the sixth grade (which would have been late 1970s). I got it from the school library. I would guess it was written prior to the late 1970s because we never had any new books at the school library. In the book, the boy meets a man who teaches him about different kinds of codes and how to break them. It included info about how people used to wrap paper around a cylinder and then write messages on the spiraled paper (so the reader would need a cylinder of the same radius to read the message correctly). It also had a tic-tac-toe type code (Different squares of the tic tac toe shape would represent different letters so an A would look like a backwards L and a B would look like a U). It also talked about E, T, A, and O being the most common letters (in English) so when you are trying to decode a message, the more commonly used symbols probably stand for one of those letters.
Stump the Bookseller
New format, same book stumper solving.
Alvin’s Secret Code.
I think this might be Danny Dunn, Invisible Boy by Raymond Abrashkin and Jay Williams.
Alvin’s Secret Code by Clifford B. Hicks. Alvin “The Magnificent Brain”, his sister, Daphne “The Pest”, and his best friend Shoie find a crumpled up piece of paper in the gutter and they are convinced it is a message in code written by spies. With the help of their neighbor, Mr. Link, they decode the message. Mr. Link explains the different methods of codes that spies have used in the past including wrapping a strip of paper around a stick and using ciphers.
definitely Alvin’s secret code by Clifford b. hicks.
Thanks! That’s it!