Book Review: "The Door into Summer" by Robert A. Heinlein

The Door into Summer by Robert A. Heinlein (Doubleday, 1957)

In one of the apae in which I’m involved through the Los Angeles Science Fantasy Society, there was some confusion recently between Heinlein’s 1940 short story “The Roads Must Roll” and his 1957 novel The Door into Summer. So I read both. The latter, which was originally serialized in The Magazine of Fantasy & Science Fiction and more recently adapted into a movie, is a slightly dated but wonderful read that combines engineer as hero, corporate espionage, and time travel.

The gist of the book is that engineer and inventor Daniel Boone Davis loses control of his housekeeping robot company through some underhanded contractual dealings involving his partner and their bookkeeper, who is also his fiancee—but not for long. To exact a revenge of sorts, Davis elects to go into suspended animation for 30 years. However, his former partner and fiancee trick him into doing so through another service provider, in order to further cheat him out of his shares of the company.

When Davis comes to 30 years in the future, he discovers that not only are some of his patents still incorporated in commercially available consumer technology—perhaps still a source of income for him—there are also some eerily similar patents that could very well be his own work, as well. Through a colleague at one of the companies still licensing technology he had a hand in developing, he learns about a professor who’s discovered a mode of time travel—and is able to get sent back in time to several months before he first went into suspended animation.

Falling in with a group of nudists in Colorado, he develops similar, competing technology, establishes another shell company, and does everything he can to provide for the future he encountered—interpreting and claiming it as his own—before he gets pulled back into the future.

Some readers might find the protagonist’s love interest problematic. Were it not for his preteen, perhaps distant relative also taking the cold sleep to reunite with him in the future—where they can finally marry as adults—most of their time together was spent as a man in his 30s and a girl of perhaps 12 or younger. He even agrees to marry her—in the future—while visiting her at a Girl Scout camp—having traveled to their past. The situation is somewhat uncomfortable and not entirely gracefully resolved through time travel. The other women portrayed in the book are either receptionists or his duplicitous bookkeeper fiancee, who’d been involved in similar crimes. 

The novel is an intriguing piece of fiction with two different forms of time travel, an interesting untangling of the time-travel paradox, and plenty of commentary on the positive contributions of engineering and engineers in overcoming challenges, solving problems, and creating a positive future. The details surrounding the “cold sleep” technology are also interesting, with its emergence from the military during a nuclear conflict that is largely glossed over.