The book describes the operational and technical and economic characteristics of the DTRD mainly with large degrees of bypass. Information is provided on ways to increase the efficiency of dual-circuit turbojet engines, methods for creating effective (with a large resource and low fuel consumption) modifications of DTRD based on a unified gas generator are considered. Much attention in the book is paid to the acoustic characteristics of DTRD and methods for reducing the noise of aircraft equipped with DTRD. The analysis of operational characteristics is illustrated by examples of foreign aircraft engine building.