Quantum theory provides the fundamental underpinning of modern physical science, yet its philosophical implications are so shocking that Einstein could not accept them. By following the historical development of 20th century quantum science, the student should gain an appreciation of how a scientific theory grows and develops, and of the strong interplay between scientific observation and philosophical interpretation. Although students will not be expected to carry out mathematical derivations, they should gain an understanding of basic quantum findings. Students enrolling in 527 must register for the recitation section that is reserved for that number, which is for graduate students.