Coming into the 21st century, developments in three major areas of elementary particle physics — the electroweak theory with the Higgs mechanism, quantum chromodynamics, and string theory began to yield more and more concrete and successful results.Seeds of all these developments in contemporary particle physics were sowed by Nambu in prophetic lectures and papers from the 1960s–70s.The discovery of the Higgs-like scalar particle at the Large Hadron Collider in July 2011 was the climax for the idea of spontaneous symmetry breaking that Nambu had laid down at the beginning of the 1960s.In this book, we collect what we consider to be the most prophetic of Nambu's papers for the benefit of current and future generations of particle physicists of the world and made them easily accessible for all. It also contains articles never published before in a book form. This text is not only of historical value but also provides a window to the mind of a man many refer to as “Nambu the seer.”A must-have book for future researchers of elementary particle theory and for those interested in the history of modern physics.