I love Wikipedia for its sense of community, its democratic ethos and its eclecticness. I love the fact that I have my own entry, which has been edited by a Danish computer scientist and a magistrate in Singapore. I love the fact that there's a project specifically dedicated to making the entries relating to Doctor Who as exhaustive as possible, and that a featured article can surprise me by bringing to my attention a culture I would never otherwise have had a clue about the existence of.
I do, however, take issue with the ideas expressed in its article on steampunk, and not having the time to edit said article to an appropriately scholarly standard at present, I intend to sound off about the fact here instead.
Feel free -- as if you wouldn't anyway -- to skip this entry if jargonistic criticobollocks concerning obscure contemporary subgenres of speculative fiction fails to interest you.
The article's basic definition -- "Fiction in the steampunk genre is set in the past, or a world resembling the past, in which modern technological paradigms occurred earlier in history, but were accomplished via the science already present in that time period" -- is actually a pretty good one, especially when qualified by the observation that steampunk is "usually set in an anachronistic Victorian or quasi-Victorian alternate history setting".
Clute and Nicholls' generally admirable Encyclopedia of Science Fiction simplifies this considerably, reducing it to "the modern subgenre whose sf events take place against a 19th-century background" [p1161]. This omits several elements which the Wikipedia entry has picked up on, including the fact that steampunk lends itself to alternative histories and that it typically -- and I would say essentially -- involves historically primitive science (often steam-driven, hence the name) taking on the functionality of modern or futuristic technologies (computers, long-distance communications, spacecraft). To be fair, though, Nicholls wrote the entry in 1993, when works of steampunk were rarer, wheras the Wikipedia article was last updated today. Clute and Paul J McAuley do better in 1997's Encyclopedia of Fantasy, where they classify the type as "technofantasy that is based, sometimes quite remotely, on technological anachronism" [p895].
The technological anachronism is, I'm convinced, the key to categorising works of S.F. as steampunk. As a genre, steampunk grew out of cyberpunk -- hence, obviously, the other half of the name -- and has the same interest in challenging authorities and creating countercultures by means including the technological. By showing these technologies arising before their time, and producing the resultant revolutions in thought against an anachronistic historical backdrop, steampunk questions the historical process by which heresies (scientific and otherwise) become orthodoxies, and countercultures enter the mainstream.
This is most obvious in one of the seminal works of steampunk, William Gibson and Bruce Sterling's The Difference Engine, which portrays a nineteenth-century information revolution centring around Charles Babbage's mechanical computer. This is explicitly contrasted with the real revolution in Victorian thinking which arose from the discovery of evolution, while the rebellious-poets-turned-establishment-politicians Shelley and Byron lay the basis for a future totalitarian regime. In an Epilogue the information itself evolves to become artifically sentient, and finds itself the tool used by this regime for the oppression of its human subjects.
All of this is fairly subtle, sophisticated stuff, and is something which the Wikipedians, dazzled by style and paying rather less attention to substance, seem entirely to have missed. As often as not the difficulty with Wikipedia lies in its very comprehensiveness, with the fact that reader / editors add to the corpus an awful lot more often than they take away. Thus the steampunk article has become ludicrously inclusive, extending the historical period and the generic referents far beyond the scope implied by that opening paragraph, to the point that it is no longer of much use to anyone.
If I were to define steampunk, I would suggest the following as essential criteria:
1. The technological anachronism of modern functionalities in a Victorian(ish) setting.
2. A strong grounding in real-world history, and the historical process.
3. A countercultural aesthetic, whether achieved directly or ironically.
The Wikipedia article is nothing like so rigorous. The idea that "the genre has expanded into medieval settings", for instance, shows a chronic (as well as a chronologic) misunderstanding of the genre's basis. The Victorian setting is important both thematically (the Victorian era itself being a time of rapid and catastrophic intellectual revolution) and aesthetically (thanks to the distinctiveness of its technologies). Extending the range to cover the whole of the nineteenth-century and the Edwardian era is probably fair enough, but a work like McAuley's Pasquale's Angel (where Leonardo da Vinci ushers in an early Industrial Revolution in Renaissance Florence), though splendid, can't be considered steampunk. I've heard it referred to as "clockpunk" as in "clockwork", which makes some sense, but it -- like "sandalpunk", "bronzepunk" and "stonepunk" -- can't be said to belong in the article.
There is a case for including works set in strongly Victorian-influenced alternative presents or futures, which rule themselves in through a close awareness of their Victorian roots and of the historical process mentioned in point 2.... but the suggested category of "fantasy steampunk", which fails altogether to engage with real-world history, is entirely spurious. A work like China Miéville's Perdido Street Station may have steam-powered A.I. robots in it, but they exist in a made-up setting alongside magicians, demons and human-animal hybrids. Its use of tropes taken from steampunk adds enormously to its richness of texture, but it's in no way an examination of technological revolution or shifts in historical thought. Instead, it uses some of the trappings of steampunk for purposes quite different from those of the genre.
Equally not steampunk, and for surprisingly similar reasons, is Stephen Baxter's The Time Ships, the "authorised sequel" to H.G. Wells' The Time Machine which I was mentioning just the other week. Whereas true steampunk arises from a close examination of the understanding and imagination of the Victorian era, Baxter's novel is essentially a work of modern hard S.F., replete with Dyson spheres, quantum multiverses, Gödelian logical systems and a complex explanation of the working physics of what was, for Wells, purely a philosophical and literary device. Wells' Time Traveller is used essentially as an ingénue to tour the universe Baxter wants to write about: what Wellsian touches there are (the "land leviathans" of the war-ravaged alternative 1930s, for instance, or the utopian social planning which the denizens of this era have in mind for when their War is over) are mere window-dressing on Baxter's late-twentieth-century story.
[The sharp-eyed may notice that the Wikipedia article against which I am supposedly railing does not, in fact, claim The Time Ships as a steampunk work. Oops. It's just that I'm rereading Baxter's novel at the moment, and this aspect of it -- the fact that it claims to be a sequel to Wells whilst in fact being the kind of novel Baxter thinks it would be more interesting if Wells had written instead -- is annoying me. I imagine some readers of Peculiar Lives may sympathise.]
This point is more widely applicable, however, as steampunk is always keen to analyse and problematise the era it's examining, and by extension the era in which it was written, giving rise to the "countercultural aesthetic" I've mentioned in point 3. As the article suggests, it might do so by techniques including dystopias or ironic utopias based on the principles of the time: it won't, however, achieve anything much by just providing a pulp-fiction romp through the era, which is why I'm suspicious of many of the films, TV programmes and rôle-playing games which the Wikipedians claim for the genre. There's very little that's countercultural or subversive about Back to the Future Part III, for example.
On the other hand, The League of Extraordinary Gentlemen almost certainly does qualify thanks to its gleefully ironic recreation of the imperial and racial attitudes of the era -- despite the fact that it's set in the continuum of Victorian pulp fiction rather than that of the historical era. This brings me to another point, which I'd add as a non-essential fourth criterion, that all of my points above are served by a metatextual relationship with the fiction of the period: works of steampunk are frequently direct sequels to, incorporate characters from, or at the very least allude heavily to, the speculative and other fiction of the era. This is as true of The Difference Engine, which features characters from Benjamin Disraeli's Sybil, as it is of LoEG.
So. What texts would be on an essential steampunk reading list? I'll be honest: I haven't read enough of the recognised classics (although some of them, like Anti-Ice and The Space Machine are on my "read soon" list) to be sure. The Difference Engine would be there, certainly, as would the two volumes of LoEG, and Brian Aldiss' Frankenstein Unbound. Michael Moorcock's Dancers at the End of Time trilogy would make it, as perhaps would his Oswald Bastable trilogy (published in one volume as Nomad of the Time-Streams). I'm not convinced about Tim Powers' often-cited The Anubis Gates because of its heavy fantasy content, although it has been a couple of decades since I last read it -- almost as long as Harry Harrison's A Transatlantic Tunnel, Hurrah!, which I suspect should be on the list. It's obviously a work in progress.
As indeed are most of the opinions above. If anyone's managed to follow me so far, then I'd be intrigued to hear what you think.