By the President's Commission. "With a special introduction by Harrison E. Salisbury and other material prepared by The New York Times," for this paperback edition from 1964, which is unabridged. I also enjoy this edition's cover photo, in which Kennedy seems to be pulling a "...really?" face at various theories about his murder.
If you've never read the WR, this is a great research copy, in decent shape for its age but priced right. The spine has cracks, but the pages are tight and the book sits pretty square; there's some creasing to the cover and some page toning and edgewear, but nothing serious.