Fifty years ago this month, the June-July 1970 issue of Science and Electronics  carried this project, which itself dated back another fifty years. It’s a simple crystal set, but the most interesting feature is the tuning capacitor, which is a book-style condenser. It consists of two blocks of wood, each with a layer of aluminum foil carefully glued to one side. These are hinged together, and the set is tuned by turning a screw to open and close the book.

Astute readers might remember similar capacitors used in this 1944 crystal set and this 1942 tutorial on making parts at home.