Natural History Books
- Rare and hard to find books, especially ornithology and herpetology.
- http://www.naturalhistorybooks.biz/

Jonathan Grobe Books
- Used and out-of-print scientific, technical and scholarly books.
- http://www.grobebooks.com/

Gary Wayner
- Used, rare and scholarly natural history books with an emphasis on botany.
- http://www.wayner.com/

Jan Meemelink
- Old, rare and second hand books and prints on botany, gardens, horticulture, and agriculture. based at The Hague, Netherlands.
- http://www.meemelink.com

Buteo Books
- Offers used, new, and rare books about birds and ornithology.
- http://www.buteobooks.com/

W. Bruce Fye
- Old, rare, and out-of-print books in medicine, surgery, and related fields.
- http://www.fyebooks.com/

Old South Books
- Specializes in old and rare medical books; based in Memphis, Tennessee, books bought and sold.
- http://www.oldsouthbooks.com/

Wheldon and Wesley Ltd
- Natural history books.
- http://www.users.dircon.co.uk/~wheldwes/

GeoLibri
- Second-hand books in geology and palaeontology.
- http://www.geolibri.com/

Scholarly Books
- Specializing in psychology, psychiatry, psychoanalysis, neuroscience and all aspects of the study of the mind and brain. Catalogues issued periodically and upon request in all fields of specialty.
- http://www.scholarlybooks.com/

David White Books
- Antiquarian and interesting out-of-print medical books; specializing in the history of medicine and pharmacy.
- http://www.davidwhitebooks.co.uk/