The book is intended for radio amateurs interested in searching for various metal objects using special equipment, which primarily includes metal detectors. The relevant sections contain schematic diagrams and drawings of printed circuit boards of both simple and more complex designs. Recommendations are given on how to independently manufacture and configure metal detectors, as well as advice on their practical use. This publication will be useful not only for trained radio amateurs, but also for all readers interested in this topic, since most of the presented designs can be made by both adults and schoolchildren, never holding a soldering iron.