The Higgs boson or Higgs particle is an elementary particle in the Standard Model of particle physics. It is the quantum excitation of the Higgs field which is a fundamental field of crucial importance to particle physics theory. The Higgs Boson was first suspected to exist in the 1960s and unlike other known fields such as the electromagnetic field, takes a non-zero constant value almost everywhere. The question of the Higgs field's existence has been the last unverified part of the Standard Model of particle physics and, according to some, "the central problem in particle physics." The presence of this field, now believed to be confirmed, explains why some fundamental particles have mass when, based on the symmetries controlling their interactions, they should be without mass. The existence of the Higgs field would also resolve several other long-standing puzzles, such as the reason for the weak force's extremely short range. This book is an overview of the background and legacy of The Higgs Boson.