The Past Through Tomorrow contains all 21 stories, novellas, and novels of Heinlein's Future History series. The four books making up the series (The Man Who Sold the Moon, The Green Hills of Earth, Revolt in 2100, and Methuselah's Children) used to be a little hard to find in the pre-Internet days, making this collection an absolute boon to Heinlein readers. In addition to the convenience of having everything in one volume, this book also includes two stories that are not to be found in my copies of the originating books: "Searchlight" and "The Menace From Earth." These are rather lightweight stories, but they are quite entertaining.
It was actually Joseph W. Campbell, Heinlein's editor at Amazing Science-Fiction, who came up with the term Future History; Heinlein did have some of the stories mapped out on a timeline, but he never intended to make this a series in any real sense of the word. Up until the final selection, these stories are largely independent of one another. With Methuselah's Children, however, Heinlein traces the tale's antecedents to his very first story "Life-Line," incorporates a few characters from other assorted stories, and casts a web of continuity over the whole package. Even still, this is only "a" future history, not "the" future history. Aspects of Heinlein's science indeed worked its way into the real world over time, but one would be wrong to label this body of work as some type of prophetic endeavor on the author's part.
The contents of this collection basically offer the reader the cream of the crop of Heinlein's early fiction. Among the stories deserving special mention here are the novella "The Man Who Sold the Moon," featuring one of Heinlein's most unforgettable protagonists, "-We Also Walk Dogs," the story of a company able to perform small miracles to meet the needs of its clients, "If This Goes On-," a tale of the repressive theocracy that followed in the wake of evangelist Nehemiah Scudder usurpation of power, and the novel Methuselah's Children which brings the vision of these stories all together. I have only one criticism of this fine collection: no special mention is made of the century-long gap between "Logic of Empire" and "If This Goes On-." The fall of American democracy at the usurping hands of Scudder is a story that Heinlein never told, so the reader may be shocked to find a forward-looking free America suddenly transformed into an anachronistic, brutal autocratic regime at the start of the latter of these two stories. In my copy of Revolt in 2100, Heinlein includes a postscript concerning the stories never written-this does much to explain the striking transition that defines the "missing century" of this Future History, and it's a shame that this postscript did not find its way into this omnibus collection.
The Past Through Tomorrow serves as a wonderfully useful map to the writing of Robert A. Heinlein. Not only does it contain the most important of his early short stories, it also sets the stage and provides the background material for Heinlein's later novels featuring the likes of the remarkable Lazarus Long.