The Manual of Free Energy Devices and Systems Volume II (often associated with D.A. Kelly) is a compendium documenting various alternative energy prototypes and "over-unity" (more energy out than in) research projects. It focuses on practical, experimental devices—such as magnetic motors and specialized transformers—purporting to harness unconventional energy sources, rather than detailed theoretical physics. The manual highlights the efforts of researchers attempting to bypass traditional energy constraints through new electromagnetic and magnetic setups, serving as a snapshot of fringe science energy research in the late 20th century.