A good overview of the technical aspects of radio. Starting with the easiest sets to construct (crystal), each successive chapter solves a problem with the previous chapter's design, eventually progressing to a superheterodyne tube-based unit (the height of technology in 1943). The last few chapters of the book discuss simple transmitter design and some of the theory behind frequency modulation (or FM) radio. You may have to take the word of the authors when it comes to building these units; it may be hard to find the specific vacuum tubes needed to complete them. My favorite part? The disclaimer on any experiment which involves transmission warning you not to hook it to an aerial, since transmitting radio without a license during wartime is illegal. ( )