“Free will and predestination in one sentence and both true.”

Forced into a thirty-year stint of cryosleep by his ruthless business partner and deceitful fiancée, resourceful electronics engineer Daniel Boone Davis awakens at the turn of the 21st century to an unfamiliar world, but not one so alien that he can’t quickly grok the modern culture and tech landscape (although it will be alien to readers for who these future years are now past). Like many Heinlein protagonists, D.B. is an idealized version of the author—staunchly individualist, diligent, imaginative, technically savvy, humorous, good-natured, adaptable, self-reliant, and hot-blooded. These qualities are precisely what make Heinlein an enjoyable author to read, and so they tend to make for enjoyable protagonists. Whether the gadgeteer is ruminating on the merits of the good old slide rule, conversing with his feline sidekick, waxing optimistic about the future of mankind, or making plans to marry a young girl after some fancy-schmancy time travel brings their ages into alignment, he carries the story along like a breeze with his cheerful prattle and witty remarks, ensuring that The Door Into Summer is supremely readable even if it isn’t quite top-tier Heinlein.