Okay, 2021 (American, college) football has officially begun and here are some adds.
I'm disregarding series which are continued by others (such as Frederik Pohl's
Man Plus having a sequel by "Frederik Pohl and Thomas T. Thomas") and series I liked but below a certain threshold (like Neil R. Jones' Professor Jameson books where I found the first four oddly enjoyable but didn't bother to get the last atypical volume) and I'll try to skip books set in the same milieu but not otherwise strongly related, which usually includes prequel series and such. Also, I'll try not to get into things like Asher's Polity where I have read all of the core Cormac books which actually exist (but little else in the milieu) but expect there to be eventually more that I won't keep up with.
So some that remain are:
Harrison's
Stainless Steel Rat. I read the first three in omnibus form and loved them and have read at least one other (with more in the Pile) but I'll probably never read all of them.
Foster's
Pip and Flinx. I liked The
Tar-Aiym Krang and feel it could have made the start of a great, short, focused series but the next two books were only okay and didn't fill me with the burning desire to read the other fourteen. (I would have been willing to read one or two more, though, if there were only one or two more.)
Pohl's
Heechee.
Gateway is one of the Greats but sequels were ill-advised. I didn't enjoy them as much and didn't read all of them.
Anthony's
Incarnations and
Xanth series... and
Apprentice Adept (three of seven)... and
Bio of a Space Tyrant (five of six). Thanks for the reminder, Victoria... I think. I can't remember how much I really loved the first books (not so much that I didn't eventually get rid of them in a momentary lapse of a book purge I sort of regret) but I did read even more than Victoria before giving up - four or five of the eight of Incarnations and probably a half-dozen of the 44 Xanth books - so I must have liked them to a great enough degree to mention.
Zahn's
Cobra and
Blackcollar. I very much liked the initial books of each but haven't messed with the belated follow-ups.
Banks'
Culture. Except for one awful chapter, I liked
Consider Phlebas quite a bit but intensely disliked
Player of Games and didn't care much for another couple, so gave up. (That will likely cause some bugged eyes on this board).
Steele's
Near Space.
Orbital Decay was fantastic (as was the collection
Sex and Violence in Zero-G set in the same universe). The sequel was not at all. I persevered through a couple of books that landed somewhere between those extremes but never got around to the somewhat belated last one.
McDevitt's
Alex Benedict/Chase Kolpath.
A Talent for War was very good and I enjoyed the somewhat different sequels that turned it into a sort of semi-annual mystery series but the seventh book seemed like a nice stopping place, so I did, but McDevitt didn't. I don't rule out getting back to them someday, though. Who knows?
Bova's
Mars. I loved the title-novel but didn't enjoy the
Return to Mars as much, so haven't read
Mars Life (if I'm correct in assuming that's a sequel like it sounds).
Reynolds'
Revelation Space. It's not so much the title-novel that I really liked, but the two milieu collections (
Diamond Dogs and Turquoise Days and
Galactic North). Either way, I'll almost certainly never read all the books. (I can't even seem to finish the initial trilogy, having gotten stuck between the second and third, though I still mean to read it in theory.) It's kind of like Hamilton's Confederation, only that's worse because I've only read and enjoyed
A Second Chance at Eden but will probably never read any of the bug-crushers that are the actual series.
It occurs to me that there are no series from before the 60s or after 2000 here. For the older ones, it seems they're more often just trilogies or so and I tend to enjoy them more. For the newer ones, I tend to avoid them. I especially dislike it when books are announced by publishers and/or authors as "first in a series" (as they often are) which assumes (a) we like paying full price for pieces of novels and (b) that we'll buy more pieces whether we enjoy the first part or not. Not to mention that it's unlikely we
will enjoy just a part that doesn't finish anything.
Older books tended to be complete in themselves and became series when fans cried "More, more!" And that's one part where I'd disagree with you, Venusian Broon. Though, ironically, Campbell did want Foundation to be a series from the start (it's different for stories in magazines), the fans agreed through the 40s. Asimov (again, ironically, in that he was sort of like Doyle with Conan) wanted to stop and eventually did for decades. Then, I believe him when he says he was quite happy to be writing easy non-fiction books and had to be practically forced into writing more SF novels. Then the fans again spoke as
Foundation's Edge hit the bestseller lists and won an award so there was little chance of refusing his beloved editors and publishers at Doubleday and turning back then. And I do think that book (like the third Robot novel) is rewarding, though I'd agree with you that, after that, he was mostly focused on welding his series together and they did start to pay relatively diminishing returns.
That does raise a related topic, asp3. I don't know if you'd already planned it but, after threads on lesser-starting series and lesser-ending series, how about starting a thread on something like "What series have you completed and actually enjoyed to a high degree from start to finish?"