Here's a list of out-of-print Colorado guidebooks from my personal library. Books that have content not duplicated in current books are highlighted, and would be useful to include on MP.com lists for present-day climbers. All the others have been superceded by more up-to-date, in-print books.
There are probably several hundred more out-of-print Colorado guidebooks that I don't own; see the American Alpine Club Library collection at americanalpineclub.library.net for details.
Books are listed by publication date.
A Climber's Guide to the Rocky Mountain National Park Area, Walter Fricke, 1971. [Great historical reference on early RMNP climbs.]
High Over Boulder, Third Edition Second Printing, Pat Ament and Cleveland McCarty, 1976.
Eldorado: A Climber's Route Guide, First Edition Second Printing, Pat Ament, 1978.
Soft Touch: A Rock Climbers Guide to the Garden of the Gods, First Edition, Mark Rolofson, 1979.
Rocky Heights: A Guide to Boulder Free Climbs 1980, James S. Erickson, 1980. [Classic guide; introduced three-star quality ratings and R, X protection ratings. The bible of my early climbing years.]
Thath-AA-Ai-Atah: A Rock Climber's & Scrambler's Guide to the Lumpy Ridge Area, Chip Salaun & Scott Kimball, 1980. [Another old classic; my Lumpy bible in the early days.]
Eldorado -- a rock climber's guide, 2nd Edition, 1st Printing, Pat Ament, May 1980.
Boulder Topographics: A Pictorial Guide to Boulder Climbs, First Edition, Richard Rossiter, 1981. [First topo guide to the Boulder area.]
The High Peaks: A Climbing Guide to the Mountain Areas of Rocky Mountain National Park, Richard DuMais, 1981. [This book, rife with errors, precipitated more epics than any other book in my collection.]
Boulder New Climbs '81, Alec Sharp, 1981.
Solitary Summits: A Climbers Guide to the Less Visited Rocks Of: Rocky Mountain National Park, Roosevelt National Forest, and Estes Park, Colorado, And a Second Title: Lumpy Ridge Revisited, Scott Kimball, 1982.
The Brown Book of Lies: A Topographical Guidebook to South Platte Rock Climbs, Peter Hubbel, 1983.
Pictorial Guide to Boulder Climbs, Second Edition, Richard Rossiter, 1983.
High Over Boulder, Fourth Edition, Pat Ament and Cleve McCarty, 1984.
For Turkeys Only: A Rock Climber's Guide to Turkey Rock, Turkey's Tail, Sheepnose and Related Crags, Steven R. Cheney, 1984.
Pictorial Guide to Boulder Climbs, Third Edition, Richard Rossiter, 1985.
Pictorial Guide to Boulder Climbs, Fourth Edition, Richard Rossiter, 1986.
Boulder Climbs, Fourth Edition Addendum, Richard Rossiter, 1986.
Lumpy Ridge and Estes Park Rock Climbs, Scott Kimball, 1986.
The High Peaks: A Climbing Guide to the Mountain Areas of Rocky Mountain National Park, Second Revised Edition, Richard DuMais, 1987.
Flatiron Classics: A Guide to Easy Climbs & Trails in Boulder's Flatirons, First Edition, Gerry Roach, 1987.
Rocky Mountain National Park: Classic Hikes and Climbs, First Edition, Gerry Roach, 1988.
South Platte Rock Climbing and the Garden of the Gods, Peter Hubbel and Mark Rolofson, 1988.
A Climber's Guide to the Ophir Wall, Allen Pattie, 1988.
Boulder Climbs North, Richard Rossiter, 1988. [Still useful, but good luck trying to find it other than at the AAC library.]
Boulder Climbs South, Richard Rossiter, 1989. [Available online at used book sellers for $55-$68].
Colorado's Indian Peaks Wilderness Area: Classic Hikes and Climbs, First Edition, Gerry Roach, 1989.
An Interim Rock Climbing Guide to Rocky Mountain National Park, Richard Rossiter, 1992.
Best of Boulder Climbs, Second Edition, Richard Rossiter, 1992.
Rocky Mountain National Park: The Climber's Guide, First Edition, Bernard Gillett, 1993.
Colorado Front Range Crags, Peter Hubbel, 1993. [Covers Poudre Canyon, Gross Reservoir, Golden Gate Canyon State Park].
1995 Boulder Sport Climber's Guide, Mark Rolofson, 1995.
Best of Boulder Climbs, Third Edition, Richard Rossiter, 1996. [Fourth edition still in print].
1996 Boulder Sport Climber's Supplement Guide, Mark Rolofson, 1996.
The Devil Made Me Do It! Climber's Guide to Devil's Head, Tod Anderson, 1998.
100 Select Classic Rocky Mountain National Park Climbs, Michael Stevens & Fred Knapp, 1998.
Rock Climbing Shelf Road, Mark Van Horn, 1999. [Available through amazon.com]
Shelf Road Rock (version 4), Fred Knapp, 1999.
Boulder Canyon Sport & Adventure Climber's Guide, Mark Rolofson, 2000. [Covers lower-canyon crags below Boulder Falls.]