Bowker is a company that provides bibliographic information and data services to publishers, libraries, and booksellers. They are known for their comprehensive databases of books and other publications, which are used by professionals in the publishing industry to track and manage their titles. Bowker also offers services such as ISBN registration and cataloging tools to help authors and publishers promote and sell their books. Overall, Bowker plays a crucial role in the book industry by providing essential information and services to help books reach their intended audience.