It was Einstein who introduced the issue of locality into the philoso phy of quantum mechanics. Although the concept is clearly suggested in his 1935 paper with Podolsky and Rosen, the discussions in the Autobiographical Notes, Reply to Criticism and 'Quantum Mechanics and Reality'-all of which appeared in the late 40's-form a much more explicit and useful guide to his thought on the subject. Each of these sources is readily accessible. Nevertheless Einstein's views are frequently misrepresented, and so a brief account is given here. In the Autobiographical Notes we are asked to consider two systems Si and S2 which have interacted and then separated. It is assumed that the interaction has left the composite system Si + S2 in a state ^12 which correlates the magnitudes of Si with those of S2. Einstein is quite explicit in allowing that in the presence of ^i2, the state function which characterizes S2 after a measurement performed on Si may depend on the type of measurement carried out at Si. Einstein refers to this possibility as something about which "all quantum theoreticians now agree" (1959a, p. 85). The contention of the Autobiographical Notes is that because of this, the ^-function must be interpreted as a description of our knowledge of "the real factual situation" at S2. In the case of two spatially separated sys tems, the real factual situation at S2 is independent of what is done with the system Si. In 'Quantum Mechanics and Reality' the assumption on which this contention depends is given something of a transcendental justification: