Post-rock is a rather vague and controversial term given to a broad range of experimental musical styles that arose in the nineties.

It was coined by Simon Reynolds in a thinkpiece that appeared in the May 1994 issue of The Wire magazine. His definition of post-rock was: music created by former rock musicians using rock instruments in non-rock ways, and often by using non-rock instruments too.

To understand this definition, we also need a definition of rock. Reynolds uses the narrow definition laid down by Joe Carducci in his book Rock and the Pop Narcotic. Carducci believes that rock is, in essence, nothing but drums, bass and rhythm guitar, working together in real time like an engine producing kinetic energy. Therefore "non-rock" is any music not made using the three rock instruments, and/or not in real time, and/or not full of rhythmic energy.

Now looking back at Reynolds's definition, we can see that it actually applies to a huge number of artists throughout rock's history, including the late Beatles, psych and prog bands like Pink Floyd, Krautrockers like Can and Neu!, dub reggae producers like Lee Perry and King Tubby, father of ambient and Roxy Music/Bowie/Talking Heads/U2 producer Brian Eno, post-punk bands like Wire and Public Image Ltd., and shoegazers like My Bloody Valentine. These artists spent a lot of time experimenting in the recording studio, overdubbing and adding effects instead of playing in real time, focussing on psychedelic textures instead of (or as well as) on energetic rhythms, and often using synthesizers and other non-rock instruments.

Influenced by these predecessors, as well as techno and hip-hop producers like Aphex Twin and Public Enemy's Bomb Squad, post-rock bands use guitars to create timbres and textures rather than riffs and powerchords. They also use modern technology like computers, samplers, sequencers, synthesizers and MIDI. The result is not music that rocks, but music that thrills us with ambient and psychedelic sounds, and sometimes grooves like jazz or dance music. Post-rock is usually instrumental, rejecting rock's tradition of vocals and songcraft, and sometimes even rejecting rock instrumentation. However, for it to warrant the name, some rock aspects must remain, lest it slip into a different category like techno or ambient, as the music of former post-rockers like Techno Animal, Thomas Koner/Porter Ricks, and Third Eye Foundation has done.

An excellent example of post-rock's blend of rock and non-rock is the music and methods of Disco Inferno. On their 1993 album D.I. Go Pop, this former rock band sang and played rock instruments together in real time, but their guitar strings and drum pads triggered samples rather than the usual sounds, creating a magnificent wall of weirdly manipulated noises. Other bands including Seefeel and Sigur Ros have expanded upon the example of My Bloody Valentine's Kevin Shields using their guitars as texture generators, creating soundscapes out of feedback, distortion and effects, and sometimes adding programmed dance beats. Bands like Low are called post-rock mainly because they are so slow and quiet, i.e. so non-rock.

An alphabetical list of bands who have been called post-rock (often controversially):
Add N to (X), Aerial M, American Analog Set, Jessica Bailiff, Bark Psychosis, Bastro, Bedhead, Bowery Electric, brise-glase, Broadcast, Childs View (Nobukazu Takumora), Circle, Codeine Andrew Colemann, Console, Couch, Cresent, The Crownhate Ruin, Cul De Sac, The Dead C, the Dirty Three, Disco Inferno, Do Make Say Think, Dylan Group, Echoboy, Evergreen, Experimental Audio Research, Flying Saucer Attack, The For Carnation, Four Tet, Fridge, Fuxa, Ganger, Gastr Del Sol, God, godspeed you black emperor!, Hair and Skin Trading Co., H.I.M., Hood, Hoover, Ice, Ida, Impulse Nine, Insides, Isotope 217, Jessamine, June of 44, Karate, King Kong, Thomas Koner, Kreidler, La Kuizine, Labradford, Laika, Laub, Lesser, Lithops, Loop, Low, Lull, Lungfish, Main, Microstoria, Mogwai, Moonshake, Movietone, Mouse on Mars, Jim O'Rourke, Palace, Panasonic, Papa Sprain, Piano Magic, Pole, Polvo, Porter Ricks, Pram, Purr, Rachel's, Radiohead, Red Red Meat, Retsin, Rex, Rodan, Rome, Ruby Falls, Schneider TM, Scorn, The Sea and Cake, Seefeel, Seely, Shellac, Shipping News, Sigur Rós, Silo, Sister Iodine, Slint, Slowdive, Smog, Sonora Pines, Squirrel Bait, Stars of the Lid, Stereolab, Talk Talk, Tarwater, Techno Animal, Thermoderm, Third Eye Foundation, Tied + Tickled Trio, To Rococo Rot, Toe 2000, Tortoise, Trans Am, Ui, Ulan Bator, Wert, Wheat, Windsor for the Derby, Windy & Carl, Wisdom of Harry, You Fantastic!

A few good post-rock albums:
Disco Inferno - D.I. Go Pop (1993)
Seefeel - Polyfusia (1994)
Tortoise - Millions Now Living Will Never Die (1996)
Mogwai - Young Team (1997)
Piano Magic - Low Birth Weight (1999)
Sigur Ros - Ágætis Byrjun (1999)
Godspeed You Black Emperor! - Lift Your Skinny Fists Like Antennas to Heaven! (2000)
Radiohead - Kid A (2000)
Hood - Cold House (2001)

The roots of post-rock:
Can - Soon Over Babaluma (1974)
David Bowie - Low (1977)
Brian Eno - Ambient 4: On Land (1982)
Wire - 154 (1979)
My Bloody Valentine - Loveless (1991)
Slint - Spiderland (1991)
Talk Talk - Laughing Stock (1991)
Aphex Twin - Selected Ambient Works 85-92 (1992)