You've had your eye on him for years. You could recognize those piercing blue eyes, the golden mane and the rippling washboard abs anywhere; he's your favorite romance novel cover model. You know in your heart that he's out there somewhere, waiting for you to find him. You just need to figure out how. It might not be easy to figure out who that is on the cover of your favorite book, but it's certainly not impossible.
Read the book, if it's non-fiction. If you are trying to track down a photograph from the cover of a non-fiction book, chances are that the text will at some point explain the image. This is especially true if you are reading a biography; chances are that the cover pictures the subject or some important acquaintance.
Look at the copyright page. The publisher of your book owns the copyright to the image on the cover and is legally required to credit the artist or photographer who created the image. You can find a line about where the image came from on the copyright page. Sometimes you can even fine information about what the image is or where it came from.
Contact the publisher and explain why you need to know who is on the cover of your book. The publisher can either tell you or give you the artist or photographer's contact information. You will probably have to tell the publisher that you need this information because you are completing historical research or interested in hiring the model yourself. The publisher will probably not help you if you explain that you are interested in the cover model for personal and romantic reasons.
Contact the artist or photographer who made the cover. The artist will be able to tell you who the model is or what agency the model was hired from. Otherwise, the artist can tell you where the photograph was taken or found. You may even find out that there was no model if you are trying to figure out who is pictured on an illustrated cover; the model might have come directly from the artist's imagination.
Track down the photograph, if the image comes from a historical archive. Some covers are illustrated with pictures that come from the Library of Congress or other historical collections. If you send a copy of the image to the librarians at the archive, they might be able to help you identify where the image came from and who it pictures. Otherwise, the librarian will be able to give you tips about how you can identify this photo yourself.