An amazingly brilliant Science Fiction author. Most of his books are a particular universe (well, more accurately, very near/similar parallel universes), in which all human beings have been wiped off planet Earth by a race of aliens known only as the Invaders in favor of the cetaceans on Earth.
In an interesting twist, his philosophy regarding technology (at least, as presented through his writing) can be summed up as: It's out to get us. As the most clear-cut example, I suggest the novella "Press Enter" (in the collection The Persistence of Vision), though Steel Beach also contains a similar theme
I own nearly everything he's ever written that I know of. My obsessive collecting habit has led me to such items as the 4 issues of Analog Magazine in which Steel Beach was printed as a serial. (But sadly not the serialized version of Titan.) One exception: I do not own a copy of Millenium, because I think it sucks.
An incomplete list of his books: (I'm not at home to look at my bookshelf)