I suppose the "update" to Appendix N is, allegedly, Appendix E from the 5th edition. I'm not going that way, I'm just revisiting my own, personal, Appendix N as it applies to not just the DARK•HERITAGE setting, but also AD ASTRA, CULT OF UNDEATH, HYBRID DREAMLANDS, REALMS TRAVELLER, ODD D&D, and my gaming tastes in general. I also thought that doing this from scratch, without referring to my previous work from back when "personal Appendix N" was a faddish thing to do, would make this a more significant update. I don't have the chance to cheat and merely copy what I wrote a couple of years go! So there may be a few discrepancies or changes, although they'll be minor, because by and large the works that laid the foundation of my tastes are, of course, still the same. I may not specifically think of all of the same titles at any given time that I'm asked, especially the ones that are more marginal, or which have the same influence as another work, but that's OK. A few minor notes before we get started:
NOTE 1: Given that this is meant to encapsulate my entire range of taste, for both fiction and gaming, and not just my fantasy gaming as it relates to a specific setting, it's meant to be a bit more broad and possibly eclectic. The actual Appendix N was meant to be the works that specifically informed D&D; my gaming tastes are broader than D&D, and therefore the range of works is too. Not to say that this is overly broad; my tastes still naturally narrow somewhat.
NOTE 2: There is going to be a fair bit of overlap between my Appendix N and the Appendix N. That's OK. In fact, its hardly surprising.
NOTE 3: My intention is also to make this a kind of "annotated Appendix N"—rather than merely list the works, I'm going to write a little sentence or two about each one, talking about what I like about it and what it specifically influenced me with. Because I'm annotating it with plenty of fluff by yours truly, I'm less concerned with "completeness" and more concerned with adding stuff that I believe I have something about which I have something at least vaguely interesting to say.
NOTE 4: Rather than alphabetical by author, I'm going to write it up in the order in which I think of it. Which will be largely correlated to the order in which it was influential on me, highest to lowest.
Tolkien, J. R. R.: What fantasy fan or gamer doesn't put Tolkien at the top of their list of influences? Few and far between, I'd wager, although for many, consciously eschewing Tolkienisms is a real thing. But even then, by so doing, you're acknowledging his gigantic place in the field, and reacting to that place rather than starting from a position that doesn't acknowledge him. I'm one of those who often consciously gives overt Tolkienisms a pass, but not because I'm necessarily doing it out of ideological fealty to sword & sorcery over high fantasy (as many do) but because I'm one of those guys who believes that Tolkien seems to have been a truly singular talent, and his many imitators end up coming off looking pretty pale in comparison. That said; his use of real life cultures disguised with a wink and gun at the audience (the Rohirrim, the Shire, etc.) is still something that I do without fail, his take on magic as being less systematic and more "plot devicey" and mythological is one that I like (it's difficult to pull off, though) and I always draw isometric setting maps that look an awful lot like Christopher Tolkien's maps that appeared with the edition of the book that I first got.
Burroughs, Edgar Rice: My favorite Burroughs stories are actually the John Carter ones, but Tarzan, Pellucidar, and even many of his one-offs and/or smaller series (Venus, Moon, Mucker, Caspak, etc.) deserve a mention here. The inventive imagination of Burroughs, his lost civilizations, his bizarre, otherworldly wildernesses, his larger than life heroes and villains and monsters and damsels in distress; there's literally nothing to not like except perhaps one thing, and Burroughs himself was quick to admit it: he really only has one story to tell, and so he tells it over and over and over again. Still, it takes a long time for it to start to wear on you, and when it does, take a break and then come back for more and it still works.
Howard, Robert Ervin: Everyone has heard of Conan, although I reckon many know him more from his bastardized cinematic appearances than from his originals. Conan is, in many ways, like a fantasy version of Tarzan, although Howard's philosophy on the virtue of the barbarian gives him a significantly different character in some ways. As much as anything, the Hyborian model of setting design has been highly instrumental to me as well; the notion of using races, cultures and nations that are transparently "calques" of various real world cultures of the past is an impressive short-hand and gives the setting a great deal of resonance that entirely fictional fantasy settings simply don't have. For what it's worth, Tolkien did some of the same thing; it's not hard to see the real world inspiration for numerous cultures of Middle-earth.
Lovecraft, Howard Phillips: Although I occasionally dig at Lovecraft for some of his poorly crafted stories and his stylish affectations, nobody can deny that his amazing imagination and the concepts that he came up with have been hugely influential on both the fantasy and horror genres, and will be most likely, into perpetuity. They're so ubiquitous that they've almost become more of an in-joke sometimes, rather than something meant to be horrifying (of course part of that is that they aren't necessary all that horrible, except when he's really on his game.) I really love the notion that contact with the fantastic, including magic and monsters (your daily commute in D&D) is not just hazardous to your hit points, but poses a psychological and spiritual toll on mortal men that is its real danger. Also; although it's been done by many others since, his notion of a secret history of the world is huge too—I love it, although I also recognize that that's difficult to pull off in a secondary world. But not impossible.
Lucas, George: The original three Star Wars movies, and the original few Indiana Jones movies—especially the actual first one—are hugely influential on how I perceive good, pulpish storytelling to be brought out of one medium and put into another (a key skill for gamers, I should say.) Not only is the pacing, the characterization, and the setting all perfect for adaptation, but they're just pretty dang fun. Sadly, Lucas himself, as well as his proteges that have followed and are following on his franchises, may well have lost sight of what made them popular and successful in the first place, but he really got it right the first time. Keep in mind, that even when playing in a space opera or other setting, there is a lot of correlation with fantasy. Star Wars, in spite of the trappings of science fiction, is more of a fantasy in most regards.
Leiber, Fritz: Sadly, the Fafhrd and Gray Mouser stories kinda peter out as the series goes on, but it takes a while to do so, and no matter how they're collected, you've still got several books worth of greatness before they start to wear thin. From the author's forward in the White Wolf Publishing omnibus collection I have of the first two collections, Leiber's purpose was to create characters that felt (to him) closer to true human nature than Tarzan or Conan. For my purposes, one of the great things about the characters Fafhrd and the Gray Mouser is that they conform to the archetypal "buddy comedy"—a genre that was prominent in slapstick form with rather unserious characters, but which evolved over time into something more mainstream. Buddy films hybridized and became less overtly slapstick, and when we see Fafhrd and the Gray Mouser, we can look at movies like Butch Cassidy and the Sundance Kid or Lethal Weapon or 48 Hours, etc. to see some similar movies, in some ways. I personally have had great success with the notion of the buddy team-up in fantasy gaming, and I think it's even better in fiction (gaming tends to be a bit more ensemble in nature rather than two co-stars—unless you have a very small gaming group, I suppose).
As a curious aside, Fafhrd and the Gray Mouser made a cameo in several Conan stories as told by Marvel Comics, although they were renamed and "Hyborianized" in order to fit. Fafhrd became Fafnir the Vanir (recall that in the Hyborian Age, the Vanir were red-headed pseudo-Vikings) and Blackrat—who's Hyborian ethnicity, as far as I know, was never established, although I suspect he was Zamorian, since after all, the Gray Mouser was a native of Lankhmar, and the Zamorian city (never named by Howard) that features in "Tower of the Elephant" is the setting for their cameo appearance.
Ludlum, Robert: Ludlum is another author who started out very strong, but petered out considerably; avoid his later books, and read his earlier "classics" instead. There's a lot of thriller writers who could be on here, I suppose, but Ludlum is the one I know best, so he's the one who influenced me most directly. Indirectly, I could probably claim Ian Fleming—I've read him, but don't remember very much of what I read; my Fleming influences are more indirect, through the movies—and John le Carré, or even Tom Clancy. It's too bad that many gamers don't read enough out of their genre to really get what makes other genres work; the fact that Gygax himself was a syncretist who didn't seem to much care where his influences came from other than that he liked them. I also think a lot of gamers would benefit greatly from knowing more about how thrillers work, how they're structured, and what makes them so exciting in the first place. To pick three novels of Ludlum's that I think best encapsulate the format, and are really quite good, I'd suggest The Holcroft Covenant, The Matarese Circle, and The Bourne Identity. Yes, the latter was made into a movie franchise that's also quite good, but it deviates considerably from the original.
Brackett, Leigh: Leigh Brackett is one heckuva writer. While she's rightly given credit in most circles for having penned The Empire Strikes Back (although apparently there's a revisionist narrative starting to make the rounds that her work was discarded and not much used; a debatable concept given that her draft is actually publicly available) I don't really think that's her best work anyway. I love her Erik John Stark series, and her concept of a pulpish solar system in general, that bears more than a simple casual relationship to Edgar Rice Burroughs' own Mars and Venus—but her approach and style was much more sophisticated. She's also a heckuva screen writer, and has penned some of the best movies of the 20th century; or at least some of the most fun, and some that stand out at the top of their genres. She did noir (The Big Sleep), westerns (Rio Bravo, El Dorado) and even some that are kind of singular, including one of my favorite old movies, Hatari! She brought real sophistication and skill to her work, though, and as I said, her approach was very different from that of Burroughs even when her settings were similar. As her husband (also a space opera pulp writer) Ed Hamilton once remarked, she often wrote stories of "a strong man's quest for a dream and of his final failure when it turns to smoke and ashes in his hands... her heroes seek something that they can never quite attain, yet their failure is not really defeat."
Leone, Sergio: Whereas the Revisionist Western has been largely turned into the Cultural Marxist Western (more insidious than the blatant Ostern), the Spaghetti Western was just a western built from a totally different point of the view than the romanticized Old West of older Western movies. Don't take too seriously the claims of film historians and academics who claim that it is a subset of the revisionist western; they actually only resemble each other by coincidence rather than by shared ancestry. Leone saw the Old West as a hard-scrabble frontier filled with morally ambiguous characters, and the Dollar Trilogy, starring a still young and not yet very famous Clint Eastwood, neatly encapsulates that notion. Where the DARK•HERITAGE setting very specifically has a number of Western elements, I think Westerns actually make for one of the best campaign models for any D&D-like game. Think about it: it's all about frontier regions, where settlers live a somewhat precarious life, with hostile savages just beyond their borders, and in need of a band of rather "rough men" to defend them—and hopefully find some sweet loot in the bargain. Change the setting just a little bit, and The Magnificent Seven is the perfect generic plot to raid for low level D&D; especially if you assume that the bandits (maybe orcs or some other savage humanoid) have some viable treasure in their lair. Rather than fortifying the town, the PCs are most likely to play "offense is the best defense" and some of the interpersonal relationships of the characters are likely moot in the new medium, but the point is that frontier exploration, semi-heroic rough men as PCs, and hostile savages is a core assumption of D&D—and it more closely resembles the Western than it does any of the fiction on which it was putatively based.