Thomas Peter Kraus was born in Surrey, England and educated at Epsom College in England. From 1963 to the end of 1971, he worked for his cousin H.P. Kraus, then the world's leading antiquarian book dealer. During his eight years there, in addition to hand handling many priceless medieval illuminated manuscripts, he handled, among other things, a copy of the Gutenberg Bible, all four Folios of Shakespeare, and a complete copy of the elephant folio edition of Audubon's Birds of America.
In January 1972, he established Ursus Books in a fifth floor walk-up at 460 West 23rd Street in New York. It was strictly a one-man show at that time. Four moves and just under 25 years later, Ursus Books is in the mezzanine of New York's Carlyle Hotel, with a branch in Soho and a staff of 25.
Among his regular clients are The Pierpoint Morgan Library, The J. Paul Getty Museum, The National Gallery in Washington and both Harvard and Yale Universities.