This volume constitutes the proceedings of the above conference, held to celebrate the 60th birthday of Yakir Aharonov. Two Nobel laureates (Norman Ramsey and Charles Townes), members of the National Academy of Sciences and Cresson Medal winners were among the speakers. Among the topics discussed are quantum reality, geometric phases and the Aharonov-Bohm effect, spin and statistics, black holes and quantum gravity. All of these are fundamental to our understanding of quantum theory and are related by being aspects of quantum theory on subjects that Yakir Aharonov has considered.