I think I own every book, including his non-fiction reminiscing books, he ever wrote. As a biologist, I still remember the thrill of reading the first one of his novels I ever picked up. While perusing the SciFi books at a Dalton's Bookstore in early 1978, I came across a paperback that featured cover art of an archaeological dig on the moon where they were excavating a dead astronaut.
I was hooked by what I used to call his hardcore SciFi. But since everyone thought I was referring to SciFi pornographer Phillip Jose Farmer, I had to change that to, "if you like your science hard in science fiction, then you will like James P. Hogan." He could deliver an imaginative speculation on numerous science unknowns, as well as explanations of theoretical "knowns" in a readily understood manner. And he understood the importance of never letting facts get in the way of a good story as he as much declared in his nonfiction "Rockets, Redheads & Revolution." Often, he would publish an end note in one of his novels explaining some of the things he wrote were not true, or not likely to be true but were needed to keep the story going. But just as likely the end note would expand upon real principles of physics that he introduced in the particular book.
James P. Hogan at some point quit his job a DEC (Digital Equipment Corporation) in which he sold mainframe computers to corporations and universities to make a living off of science fiction --- one of the few people to successfully do this full time.
Hogan was also referred to as a libertarian SF author. He had a strong libertarian streak and themes in several of his books, but he soured somewhat on it as a practicality believing libertarianism could never be adopted by people conditioned to something else. But early on in his career (1982) he published a great libertarian SF novel, "Voyage From Yesteryear." In it he wrote about the only libertarian society he could imagine evolving --- one in which humans with no preconceived notions logically grew up and adopted a culture of their own, unaware of the world we know and accept. I once remember a non-libertarian friend of mine who after finishing my copy said he was amazed that this fictional society proposed by Hogan's . . . could actually work!
He extended this theme in a couple of other novels in which robot societies struggled with freedom and tyranny, and human interference: "Code of the Lifemaker" and "The Immortality Option." And he wrote two back to back spy novels that were amazingly gripping and full of comments on tyranny and anti-government themes: "Endgame Enigma" and "Mirror Maze." ["The Proteus Operation" might be considered a third spy novel.] He also did his end of the world thing, that seems popular with SciFi authors in their 50's: "Cradle of Saturn" and "The Anguished Dawn." There were several human-machine interface novels, including a virtual reality universe that became the third sequel to "Inherit the Stars," "Entoverse." This demonstrated Hogan's preoccupation with speculating where humans were evolutionarily headed.
I am a voracious reader. Not a surprising trait in a libertarian. While my libertarian friends may not know it, my other friends generally do. I am not a paperback reader. While I own many hundreds of paperbacks, if there is a hardback version that is usually what I buy and read. It was my desire to read Hogan's latest which were always available in hardback about nine months before the paperback came out that started me on this preference for a bigger book to lug around and read.
I emailed Mr. Hogan on several occasions the past fifteen years. Usually after finishing one of his latest novels. He always wrote back a thank you response even though my email did not really intend a reply. He included comments that made if clear it was from him and not his publicist.
I will miss him. I have not read his presumably final novel, "Migration" that was released in May. While I enjoy rereading several of his novels, I find it sad that I cannot continue to look forward to future novels, unless we find a way to slide into those parallel Earths eh, James? Hummmm, motivation . . . .