William H. “Bill” Patterson Jr., author of the Hugo-nominated Robert A. Heinlein: In Dialogue With His Century, Vol. 1 (1907-1948): Learning Curve, died April 21, only a month before the second and final volume of the biography will be released.
Full obituary to follow.
[Thanks to Michael J. Walsh and Joseph T. Major for the story.]
Update 04/24/2014: Click here to read my tribute to Bill.