Proto-Prog

Rock Bands in existence prior to 1969 that influenced the development of progressive rock. The late 60's was a predominately experimental period for music. These bands were moving in a stream that eventually led to prog. The influence could have come from new sophisticated forms of writing and playing music, recording techniques, new instruments and vocal harmonies to name a few. Some of these bands became progressive rock bands themselves others did not.

http://www.progarchives.com/subgenre.asp?style=37

Proto-Prog 20 key studio albums

4.76 WHO, THE Quadrophenia (1973)	4.42 DOORS, THE The Doors (1967)	4.34 BEATLES, THE Revolver (1966)	4.30 BEATLES, THE Abbey Road (1969)
4.25 BEATLES, THE Sgt. Pepper's Lonely Hearts Club Band (1967)	4.21 DEEP PURPLE In Rock (1970)	4.27 WHO, THE Who's Next (1971)	4.21 BEATLES, THE The Beatles (1968)
4.65 SPIRIT Twelve Dreams of Dr. Sardonicus (1970)	4.16 BEATLES, THE Magical Mystery Tour (US Version) (1967)	4.09 DEEP PURPLE Machine Head (1972)	4.31 VANILLA FUDGE Renaissance (1968)
4.16 WHO, THE Tommy (1969)	4.23 PROCOL HARUM Procol Harum (1967)	4.26 TOUCH Touch (1968)	4.17 BROWN BAND, THE ARTHUR The Crazy World Of Arthur Brown (1968)
4.11 PROCOL HARUM Shine On Brightly (1968)	4.07 IT'S A BEAUTIFUL DAY It's A Beautiful Day (1969)	4.01 DOORS, THE Strange Days (1967)	4.20 JEFFERSON AIRPLANE Crown of Creation (1968)