Boron Arsenide offers very interesting electronic properties, as well as a high thermal conductivity; nearly 10 times higher than that of silicon. It has been hailed as 'the best semiconductor material ever found'. The present book presents a detailed review of this material and its potential applications. The materials covered include Icosahedral Boron Arsenide, Hexagonal Boron Arsenide, Amorphous Boron Arsenide and Cubic Boron Arsenide. The book references 166 original resources with their direct web links for in-depth reading. Keywords: Boron Arsenides, Electron Mobility, Hole Mobility, Band-gap, Monolayers, Defects, Mechanical Properties, Photo-electrodes, Thermal Conductivity, Heat-spreading.