All-Terrain Adventure Vehicles
was written in 1972 by John W. Malo. It was an all encompassing book that detailed multiple facets of traveling over difficult terrain. The book had chapters on four wheel drives, dune buggies, trail bikes, mini bikes, three wheelers, snowmobiles, airboats, canoes, etc but of particular interest to us were four chapters on ATVs.
They are posted below and have some great pictures and information on multiple brands of six and eight wheelers. If you look on ebay, amazon, etc you can probably find a copy for yourself still floating around but the book itself is out of production.