Origin of Mass and Strong Coupling Gauge Theories (SCGT15): Proceedings of the Sakata Memorial KMI Workshop Sakata Memorial Workshop on Origin of Mass and Strong Coupling Gauge Theories Nagoya University, Nagoya, Japan, 3 - 6 March 2015 : World Scientific Publishing : 9789813231450 : 9813231459 : 16 Dec 2017 : This volume contains contributions to the workshop, which was largely focused on the strong coupling gauge theories in search for theories beyond the standard model, particularly, the LHC experiments and lattice studies of conformal fixed point. The main topics include walking technicolor and the role of conformality in view of the 125 GeV Higgs as a light composite Higgs (technidilaton, and other composite Higgs, etc.). Nonperturbative studies like lattice simulations and stringy/holographic approaches are extensively discussed in close relation to the phenomenological studies.After the discovery of 125 GeV Higgs at LHC, the central issue of particle physics is now to reveal the