Title: The Door Into Summer - Novel
Written: October-December 1956  Pages: 639
 
Description:
Part 1, 290 pages, contain notes and synopsis, titled “A Very Small Difference”. Draft of mss with extensive edits and cross-outs.
Part 2, 267 pages, contains a draft of mss, no edits.
Part 3, 82 pages, contains some revised pages, an article about suspended animation referencing “Door Into Summer”, intro by David G. Hartwell, a real version of “Drafting Dan”.
 
Publication: 
Serialized in The Magazine of Fantasy and Science Fiction in October, November, December 1956 and published by Doubleday in 1957; a Gregg Press edition was published in1979 with Introduction by David G. Hartwell; Issued by SFBook Club as part of A Heinlein Trio.
 
Notes:  Working titles: Small Difference and Perchance to Dream.