National Audubon Society Guides to North American:

• Mammals by Whitaker, 1980, 745 pp.
• Birds (Western Region) by Udvardy, 1977, 852 pp.
• Reptiles & Amphibians by Behler and King, 1979, 743 pp.
• Insects & Spiders by Milne and Milne, 1980, 989 pp.

• Four books sold as a set
• $35