Note: This page is incomplete and is under construction. The books listed below are those that I have personally used. This list is not exhaustive, but it will serve as a useful starting point.
Field Guides
Birds
Ali Salim and Ripley Dillon S., Handbook of the birds of the Indian subcontinent (Compact Edition), BNHS, 1984
Ali Salim and Ripley Dillon S., Pictorial Guide to the Birds of the Indian Subcontinent, BNHS, 1995
Ali Salim, The Book of Indian Birds, BNHS, 12th edition, 1996, Rs. 395
Grewal Bikram, Birds of the Indian Subcontinent, Gulmohur Press, 1995, Rs. 425
Grimmett Richard, Inskipp Carol and Inskipp Tim, A Guide to the Birds of India, Pakistan, Nepal, Bangladesh, Bhutan, Sri Lanka, and the Maldives, Princeton University Press, 1999
Snakes
Whitaker Romulus, Common Indian Snakes, Macmillan Co. Of India Ltd., 1978
Deoras P.J., Snakes of India, National Book Trust, 1991, Rs. 36
Daniel J.C., Book of Indian Reptiles, BNHS, 1983
Smith M.A., The Fauna of British India, Ceylon and Burma, including the whole of the Indo Chinese sub-region. Reptilia and Ambhibia Vol. 3, reprinted by Natraj Publishers, 1943, Rs. 250 Still the most useful book for field identification of Indian snakes.
Mammals
Prater S. H., The Book of Indian Animals, BNHS, 1971
Butterflies
Haribal Meena, Butterflies of Sikkim, 1991
Gay Thomas, Kehimkar Issac and Punetha Jagdish Chandra, Common butterflies of India, Oxford/WWF, 1991
Information on National parks
IUCN, Nature Reserves of the Himalaya and the Mountains of Central Asia, IUCN, 1993
Sinclair et al, Insight Guides: Indian Wildlife, Apa Publications, 1991