There are 4 out-of-print books on the Thurstons: Brown, Thurston, compilier. Thurston Genealogies (1635-1880), Portland, Me, B. Thurston, and Hoyt, Fogg & Donham, 1880 ; and his second book -Thurston Genealogies (1635-1892)Portland, ME, 1892; Ancestry of Walter M. Thurston, by J. H & W. M. Thurston, 1894; Thurston, Charles. Descendants of Edward Thurston the first of the name in the Colony of Rhode Island, 1868. These titles are available from two reprint companies either in book or CD form. (email me if you can't find them via your search engine)
Or check out Dawn James' web site: "Thurston Genealogies 1635 and Beyond" ( http://thurston_family.tripod.com
) She's in the process of transcribing the Thurston Genealogies by Brown. Perhaps she would know if any documentation still exists for Brown's books.
There are VT Thurstons going back to Daniel Thurston in my line. My great-grandmother was Ida Thurston Clark who lived to be 98 years old in 1958.