The proposed publication is a reference book of an applied nature and therefore does not pursue scientific, but purely practical goals. The material in the book is presented in two parts. The first is a collection of unique ancient technological operations when working with iron and non-ferrous metals. The style of presentation in this part of the book is preserved in relation to the original, and references to chemical reagents and literary sources of pre-revolutionary times should not confuse the reader, since at present access to them is not an insurmountable obstacle. The secrets of many of the technologies described in the first part of the book were lost, forgotten or stored in closed archives, and the author of the book can claim that the modern generation of technicians, jewelers and home-made workers are not familiar with most of the printed recipes and technological operations. The second part of the book (appendix) is a reference guide for engineering and technical workers, engaged in soldering of various materials in the fields of mechanical engineering and radio equipment manufacturing. The information presented in this part of the book was published in numerous literary sources, and the compiler of the reference book made an attempt to collect unique materials together. The emphasis in this part of the book is on soldering, since in some cases it provides higher reliability than welding. When rational combinations of materials and solders are used and structures with optimal overlap area are used, the reliability of soldered joints is 4...25 times higher than welded ones. At the end of the book there is an extensive bibliography, reference to which will undoubtedly deepen the knowledge and experience of those involved in experimental, restoration and repair work at home and at work.