Title: Dirac, Anti-Matter and You - Article
Written:  Commissioned in May 1974 by Encyclopedia Britannica, Inc. for their Compton Yearbook; researched and written in July -September 1974    Pages: 1198
 
Description:
Part 1, 235 pages, contains notes, notecards, and calculations.
Part 2, 155 pages, contains newspaper and magazines article clippings used for research. 
Part 3, 302 pages, contains correspondence asking RAH for a 1500 word article (Heinlein went 4000 words), a partial copy of the 1974 Compton’s Yearbook, more correspondence about changes and edits to the article, and pictures included with the submission.
Part 4, 224 pages, contains several manuscript drafts with extensive edits. Discarded pages from manuscript.
 
Publication: 
Compton Yearbook 1975. Collected into Expanded Universe in 1980. Drafted at 4300 words and cut to 1,500, then expanded to 2000 words for publication.
 
Notes: Alternate title: “Paul Dirac, Antimatter and You”