This short but revealing biography tells the story of Kurt Mendelssohn FRS, one of the founding figures in the field of cryogenics, from his beginnings in Berlin through his move to Oxford in the 1930s, and his groundbreaking work in low temperature and solid state physics. He set up the first helium liquefier in the United Kingdom, and did fundamental research that increased our understanding of superconductivity and superfluid helium. Dr. Mendelssohn's vision extended beyond his scientific and technical achievements; he saw the potential for growth of cryogenics in industry, visiting China, Japan and India to forge global collaborations, founded the leading scientific journal in the field and established a conference series which still runs to this day. He published two monographs which remain as classics in the field. This book explores the story behind the science, in particular his relationships with other key figures in the cryogenics field, most notably Nicholas Kurti at Oxford, and his work outside cryogenics, including his novel ideas on the engineering of the pyramids.