Lecture 2 of Leonard Susskind's Modern Physics course concentrating on Quantum Mechanics. Recorded January 21, 2008 at Stanford University. This Stanford Continuing Studies course is the second of a six-quarter sequence of classes exploring the essential theoretical foundations of modern physics. The topics covered in this course focus on quantum mechanics. Leonard Susskind is the Felix Bloch Professor of Physics at Stanford University. Complete playlist for the course: youtube.com/view_play_list?p=189C0DCE90CB6D81 Stanford Continuing Studies: continuingstudies.stanford.edu/ About Leonard Susskind: www.stanford.edu/dept/physics/people/faculty/susskind_leonard.html Stanford University channel on YouTube: www.youtube.com/stanford