Abundant free energy. Ulrich F. Sackstedt presents energy conversion methods from sources that are still barely accepted by conventional physics. These could avert the looming scenario of future energy shortages. An ever-growing number of independent researchers and technicians are working on implementing ideas for harnessing the abundant energy that surrounds us. The author explains the fundamentals of the quantum ether concept and presents future technologies for energy conversion and utilization, as well as for information transmission and material techniques. Several guest contributions from experts in the field of space energy contextualize the topic. Lesser-known insights from Nikola Tesla and Viktor Schauberger, the pioneers of free energy, are also discussed.