Through just a handful of papers, Ettore Majorana left an indelible mark in the fields of physics, mathematics, computer science and even economics before his mysterious disappearance in 1938. It is only now that the importance of Majorana's work is being realised: Majorana fermions are intensely studied today, and his work on neutrino physics has provided possible explanations for the existence of dark matter. In this unique volume, Salvatore Esposito explores not only Majorana's known papers but, even more interestingly, unveils his unpublished works as well. These include powerful methods and results, ranging from the atomic two-centre problem, the Thomas-Fermi model and ferromagnetism to quasi-stationary states, n-component relativistic wave equations and quantum scalar electrodynamics. Featuring biographical notes and contributions from leading experts Evgeny Akhmedov and Nobel Laureate Frank Wilczek, this fascinating book will captivate graduate students and researchers interested in frontier science as well as in the history of science.