The book tells about the history of scuba diving, about warships that sank into the abyss of the oceans and seas in order to strike at the enemy from there, about the exploits of Soviet sailors accomplished during the Great Patriotic War. The types of submarines, their structure, weapons, the capabilities that submarines possess today and will possess tomorrow - all this is discussed in the book, which invites young men who are considering life to devote their lives to serving in the nuclear missile-carrying submarine fleet of the Soviet country.