The gas turbine engine and its conventional variants (turbojet, turbofan, turboprop, and turboshaft) provide an effective means for thrust and power delivery for a wide number of atmospheric flight applications. In this chapter, the design and performance analysis of gas turbine engines will be introduced, with the turbojet engine as the primary focus (detailed analyses of other gas turbine variants are introduced in subsequent chapters). The principal components of a conventional gas turbine engine are examined in some detail (intake, compressor, combustor, turbine, exhaust nozzle). Other components that are sometimes utilized by turbojet engines (and other variants), such as an afterburner placed between the turbine section and exhaust nozzle, are also discussed.