The book considers questions of protection against radioactive radiation from the physical, chemical, and biological points of view. Commercial electronic dosimetric apparatus and procedures for its use are described. Information is presented on the principles of nuclear physics and electronics needed by a reader who is not specially trained in these fields. The book is intended as a text for students in mining-metallurgy of other special-ties connected with the use of radioactive isotopes and radiation, and also for engineering-technical workers. (Author).