This publication provides an overview of plasma physics and technology aspects of the Deuterium-Tritium fuel cycle in magnetic fusion devices, from ITER to demonstration fusion power plants. The TECDOC also provides contributed papers from experts representing a wide range of international magnetic confinement fusion research and development programmes working on the D-T fuel cycle. This publication is intended for scientists and engineers working on fusion R&D, as well as private sector companies working in fusion energy development areas.