Leptons and quarks : Special Edition Commemorating the Discovery of the Higgs Boson The book Leptons and Quarks was first published in the early 1980s when the program of the experimental search for the intermediate bosons W and Z and Higgs boson H was formulated. The aim and scope of the present extended edition of the book written after the experimental discovery of the Higgs boson in 2012 is to reflect the various stages of this 30+ years search. Along with the text of the first edition of Leptons and Quarks it contains extracts from a number of books published by the World Scientific and an article from On the concepts of vacuum and mass and the search for higgs . The book is unique in communicating the Electroweak Theory at a basic level and in connecting the concept of Lorenz invariant mass with the concept of the Extended Standard Model which includes gravitons as the carriers of gravitational interaction.