After a broad overview, each chapter of Two Stroke Power Units details a particular engine subsystem. Information includes various technologies in use, their manufacture, and their performance. The information is, of course, dated - neither fuel injection or emissions are discussed, as they are both relatively modern subjects. That said, most systems - e.g. pistons, rings, ports, crankshafts - have not changed enormously since the writing, making this book a useful overview of two stroke engine mechanics, and certainly an excellent reference for anyone working with older engines.