BLPC British Library Catalogue, online. A huge 30 million book database from several libraries, including older works, 7thC onwards Cambridge University Library Online catalogue and lots more. A fast search engine, but not the easiest to use. All the online libraries around the world, organised geographically. British Thesis - needs individual local registration at Cambridge University Library Index to all theses for higher degrees in British universities UMI Dissertation Services with local Cambridge University access to the Abstracts Database Supply information about USA dissertations and theses.
Some services cost money.
Publishers' Catalogues Home Page All the publishers in the world. Well, all who have linked up. CBD home page Great discounts on Biblical Studies books, and a searchable catalogue. Good source for anything academic. The big one.