Some books are timeless, others, however, constantly remind you that they were written in a certain era. That is not necessarily wrong, though, and I think that Chronicles of Amber by Roger Zelazny are of that kind. In the first book of the series, Nine Princes in Amber, there are certain things like the style and language of the narrator, its philosophical and psychedelic themes, and the specific references to our world that seem to scream "This was written in the 70s!"
Nonetheless, the book(s) have outlived their time, and they are still a classic of fantasy, and through their (sometimes quite indirect) influence, they have helped shape a lot of contemporary fiction, and not only novels but also games, from D&D to Games of Thrones.
Now, for those who have not read the book, the basic plot of the book is about Corwin, the amnesiac member of a dysfunctional family of nine chainsmoking god-like brothers (there are also fours sisters who don't seem to matter that much) who fight over the crown of Amber, the real City of the real Earth. Apparently, almost as if it were the center of creation, Amber is the original archetype of a City, and all the other worlds, cities and civilizations (including our own planet) are a "shadow" of Amber, who is said to cast its shadow everywhere. The princes of Amber (the former king, Oberon, is currently AWOL) have some pressing sibling issues, but they are also stronger, smarter, and more powerful than any other human -real or from the shadow worlds- and in these worlds they are usually mistaken for gods, a belief the princes do not try to deny. Beyond all that backstabbing, there are also hints of something bigger going, like references to odd shadow beings, and something about "Chaos," but that's for the next books in the series.
About the book itself, I think that The Nine Princess of Amber (the first of the Amber series,) like other Zelazny's books, goes from impressive to clearly not so good in an instant, and the changes back again. It has parts clearly written by someone with a great knowledge of the craft, and then others that seem like someone is translating the instructions for a Chinese dishwasher. Although I'm sure other people may disagree, I think the quality of the book follows a V-shaped form. It starts great, with all that hardboiled gumshoe action, and it still great even when it suddenly gets so weird that even Philip K. Dick would shake his head in despair, but then (just when the action and the epic battles start,) the quality goes down. Perhaps it was just me, but there was a moment I got the impression I was reading the description of a spreadsheet of distances, time, weather, and casualties tabulations, not a real war to conquer the most important city in the multiverse.
Still, the failed invasion that Bleys and Corwin attempted fails quickly, and we find our beaten and blinded protagonist in a dungeon. I've read some people criticizing that part, usually because they believe it's boring ("where's the action!") but I think it's not only interesting but also necessary. Corwin's suffering humanizes him and gives him a certain personality and motivation he had lacked before. Sure, we know that his brothers had been fighting over some crown or somesuch for centuries, but we have no reason to care about that struggle. In fact, the whole thing is a bit solipsistic because it's almost as if there were only nine people alive in the whole Universe and the whole point of existence was just that crown and the brothers hating each other until the end of time.
"Thus did I bear Sir Lancelot du Lac to the Keep of Ganelon, whom I trusted like a brother. That is to say, not at all."
(that quote is not from the first book but the second one, but it would be a crime not to use it.)
Making him fail, and hard, is a perfect way to humanize him, to make him weaker and, yes, "normal," to give him a distinct character compared to that of his other brothers. That is why in the previous post I commented that you should read the first two books as one since the first one clearly looks like an introduction.
All doors lead to Sigil.
Roger Zelazny appeared in the fabled Appendix N but -unlike a more definite influence of Jack of Shadows on the thief class- trying to find how the Amber Chronicles shaped the original Dungeons & Dragons is a bit more difficult (to me, anyway.) But it did end up influencing D&D a lot, even if years later. A kind of time-warping retroactive influence that I'm sure Zelazny would have enjoyed.
In 1994 the Planescape Campaign setting was published, and with it the city of Sigil, The City of Doors:
"Sigil: the City of Doors. This town's the gateway to everything and everywhere that matters. Step through one door and enter the halls of Ysgard, or turn down a particular alley and discover the Abyss."
From the Player Guide to the Planes
And then there's this:
"The multiverse is a big place, and logically it has to be because hypothetically it encompasses every AD&D campaign world ever created, whether these are made by TSR or by any of the thousands of DMs who play AD&D games. This is all theoretical, of course, since no one has recorded all the campaigns created for the AD&D game, yet theoretically, they're all out there somewhere."
From the "A DM Guide to the Planes."
Although I haven't found any prove that David "Zeb" Cook was influenced by Zelazny's work when he designed the Planescape setting, it's hard not to think of Amber when reading about Sigil. The second quoted part also reminds me of those debates concerning the nature of the shadow worlds. Are they real, or are they a creation of the Princes of Amber who by conceiving them create them? It does not matter, or so the argument goes, what matters is that theoretically every world/campaign ever imagined or to be imagined should be there, somewhere. And in the center of it all, Amber/Sigil.
Then, in 1999, what is sometimes considered one of the best computer role-playing games, was published. It was Planescape Torment, and this is what his main writer (Chris Avellone) said about his influences:
"Zelazny was probably the biggest influence, since he was pretty much the master of writing stories with amnesiac heroes coming into their own.”
The Nameless One, Planescape Torment protagonist, is not only an amnesiac who has lived hundreds or thousands of lives on different worlds/planes, but he (like Corwin) also has an incredible regenerative power. Unlike Corwin, however, power (e.g. Amber's throne) isn't the goal he seeks but to understand who he is (unlike Corwin, he doesn't regain his memory in the introductory chapters.) Also, his regeneration also seems to have some limits because he looks live he routinely sleeps in a combine machine, probably the inevitable result of his body having being destroyed hundreds of times.
The main theme of the game, the question "What can change the nature of a man?", that repeats itself through all of Nameless One's amnesic reincarnations and hunts him everywhere he goes, is probably a direct reference to something written in the second book of the Amber series, The Guns of Avalon:
"Why had no one ever come up with a way to change the basic nature of man? Even the erasure of all my memories and a new life in a new world had resulted in the same old Corwin. If I were not happy with what I was it could be a proposition worthy of despair."
Changing or not the nature of man, I'm glad that a book that was written almost fifty years ago and in a very specific style and era, still casts its shadow after all that time.