Art Rock
In progs earliest carnation, it was known simply as "art rock", once the term "progressive rock" was adopted "art rock" became the term to describe bands who obviously have many progressive elements, but do not fall into any of the other categories or sub-genres. Art rock is a very loose term, and very few art rock bands have much in common, and weither they qualify as prog or not is really a matter of opinion.
Examples: Radiohead, Queen, Roxy Music, Rush, Captian Beyond, Brian Eno, Family, Mars Volta, Muse, Uriah Heep, Utopia, Kansas, Curved Air, The Long Hello, High Tide, Babe Ruth, Vangelis, Kate Bush, Super Furry Animals.
Canterbury Scene
In the kentish town which is the home to the church of Englands archbishop, there was a small but influencial musical movement known as the canterbury scene, most of the musicians involved were part of fraternities and knew each other personaly, many of these musicians formed some of the most talented british bands from the post-pyschedelic era during the 60s and 70s. One of the early canterbury scene bands was The Wilde Flowers, featured many of the musicians which would form two of the most important bands later on in the movement, Caravan and The Soft Machine. The similarities between the canterbury bands are not overwhelming, but each band has a good dose of jazz influence, especialy The Soft Machine, which are seen by some as a prototype fusion band. Also, folk music is a major influence on some bands from the canterbury scene as well, though not as prominently. Canterbury is seen by many as one of the precursers to jazz fusion.
Examples: Caravan, Soft Machine, Gong, Hatfield And The North, Khan, Matching Mole, Egg, The Wilde Flowers, National Health, Supersister.
Jazz Rock/Fusion
Not all fusion is rooted in progessive rock, obviously, this paticular type of fusion however is the fusion of jazz with progressive rock. Blending two very technical styles together creates a genre composed of some of the most amazing musicians out there, The Mahavishnu Orchestra is a prime example. The music is extreamly complex, and features some of the best musicians in fusion.
Examples: Mahavishnu Orchestra, Weather Report, Brand X, Bauhaus, Colosseum, Dixie Dregs, Wigwam, Planet X, Area, Return To Forever.
Italian Prog
As bands like Yes and King Crimson were gaining media attention in their native England, Italian musicians took part in their own prog movement around the same time, and a lot of new progressive music still emerges from Italy today, and as one would expect, the lyrics are almost entirely in Italian. Some consider Italian prog a sub-genre of it's own, since it's quite different in style from most European and North American prog. Italian symphonic prog is different from the symphonic prog that emerged from England at that time, the compositions in Italian prog often follow traditional italian arangements and the composition style of italian classical music and folk music, the movement was nationwide, emerging from several different regions of the country rather than just certain cities. Because italian prog is very versatile and many italian prog bands are different from others, italian prog styles can and often do fall into other sub-genres of prog as well.
Examples: Premiata Forneria Marconi, Banco Del Mutuo Soccorso, Il Balletto Di Bronzo, Museo Rosenbach, Le Orme, Quella Vecchia Locanda, Semiramis, Goblin, Celeste, Maxophone.
Indo-Prog/Raga Rock
The 60s were some wild times, american culture was rapidly being influenced by the excess of pyschedelic drugs, LSD and cultures from around the world. Thanks in most part to the hippie counterculture, indian music was introduced to western audiances, The Beatles began to incorperate heavy indian elements in some of their songs and music festivals like monterery pop, woodstock and the concert for bangladash had indian musicians like Ravi Shankar performing alongside rock musicians and performing for rock audiances who were not familiar with indian culture or raga music, it was this new found interest in indian music that birthed the sub-genres Indo-Prog/Raga Rock. While The Beatles used indian elements in some of their songs (Such as Love You To and Within You Without You) more progressive bands began pushing the same dynamic to a more extreme level, instead of a song or two bands began using elements of raga in all their songs, with more use of indian scales and instruments (Sitar, Tabla, Tamboura, etc) and spiritual themes common in indian music. These bands featured several talented raga musicians, blending raga with progressive rock, and there were often jazz and pyschedelic elements as well. All these bands incorperate the common structures of indian music such as repetitive circular rhythms, the use of patterns, ornamentation and long endlesss improv.
Examples: Quintessence, Magic Carpet, Shaki, Flute & Voice.
Krautrock
The common term for the German prog movement of the 1970s, bands like Kraftwerk, Faust and Neu! pushed the limits of progressive rock and popular music as well...Showcasing the sonic possibilities of synthesizer's, sampling, overdubs and electronic music as we know it. One of the first innovators in this movement was Can, who are one of the earliest examples of electronic music....The amazing impact and influence of krautrock is not limited to prog...Krautrock helped give way for new wave, techno, industrial rock, ambient music and even post rock. Krautrocks roots are mostly in avant garde and pop music.
Examples: Kraftwerk, Tangerine Dream, Can, Faust, Neu!, Grobschnitt, Amon Duul II, Ashra, Kraan, Birth Control, Agitation Free.
Math Rock
Math rock is a sub-genre to prog which is usually made up of independent bands and musicians, it is known for it's sheer complexity, unusual rhythmic structures, angular and dissonant riffs and stop/start dynamics. Though bands like Rush and No Means No are considered math rock by some, the true movement began in the 90s, the most active movements took place in Chicago, Minneapolis and Buffalo. And math rock was and still is mostly exclusive to independant labels only, though some big label bands such as Tool and System Of A Down use math rock elements. The music isn't rooted in just progressive rock however, the actual movement grew from the noise rock scenes in Chicago and other midwestern towns during the 80s and 90s, several japanese rock bands are also influencial to math rock. Among the biggest influences on math rock include John Cage, Igor Stravinsky and other avant garde musicians, as well as the super complexity of King Crimson and Frank Zappa. Math rock is never in 4/4 time. Common time signatures in math rock include 7/8, 11/8 and 13/8.
Examples: Slint, Polvo, Don Caballero, Lynx, Shellac, Craw, Dazzling Killmen, Zeni Geva.
Neo Progressive
The term to describe the great prog revival of the 80s. Neo-prog (As it is often called) is very retro in style but with more pop elements than the progressive rock of the 60s and 70s... And most neo-prog bands can fall into any other sub-genre in prog, such as symphonic prog or space rock.
Examples: Marillion, IQ, Pendragon, Arena, Satellite, Collage, Pallas.
Post Rock
Post rock is avant garde rock music with a lot of ambient and electronic elements. Weither or not post rock is a true genre is often the matter of debate, those who dont consider it a genre of it's own consider it experiemental rock with some similarities but not enough to be put into one category, still, some disagree. Post rock is very hard to describe, the term "post rock" was invented by music journalist Simon Reynolds to describe a new form of music that was emerging during the 90s, which "used traditional rock instruments for non rock purposes" as he described it. Post rock bands use their instruments as facillitators of timbres and textures rather than riffs or chords, favoring drones and ambient soundscapes over scales and rhythm...One of the founding bands of the movement was Tortoise, bands like Sigur Ros and Godspeed You Black Emperor! have since defined the modern movement.
Examples: Tortoise, Mogwai, Sigur Ros, Godspeed You! Black Emperor, Explosions In The Sky, A Silver MT.Zion, Magyar Posse.
Prog Folk
Folk music took the world by storm in the 60s, on both sides of the atlantic. While innovators like Bob Dylan, Joni Mitchell, Neil Young and others fused rock with North American folk music. British progressive rock musicians began to do the same, but with English folk instead. The most important of these bands was Jethro Tull, tull began as a blues rock band before focusing their attention towards traditional English folk music and other styles...Their defining moment was with Aqualung, with proto metal anthems like the title track and Locomotive Breath mixed with softer ballads all with a strong social message. Tulls sucess continued with Thick As A Brick and A Passion Play. Other prog folk bands include The Strawbs and Traffic, these bands rarely share the same influences, these prog bands can take elements of everything from bluegass, jazz and blues to renaissance music and other forms of traditional European music. Prog folk is still active today. Bands like Blackmores Night and Mostly Autumn have had some success.
Examples: Jethro Tull, The Strawbs, Traffic, Aphrodites Child, Blackmores Night, Mostly Autumn, Gryphon, Los Jaivas, Comus, Mezquita, Fairport Convention.