Gray's Anatomy is one of the most consulted books on human anatomy. Gray's was first published in 1901 and then followed up in 1918 with a larger, more diagram based edition. Now, Gray's is up to it's 39th edition and is still widely used as an adjunct to serious body modification research.
High quality folio facsimiles of the original editions (1:1 photographic reproductions of the original plates/pages) can be purchased for as little as $10 since the original editions are generally in the public domain. Folio facsimiles will tend to be slightly more useful since they're larger (as in atlas sized, which is very appropriate since the work is in a sense an atlas of the human body). Regardless of edition, Gray's Anatomy is still a complicated and long read because it describes a complex system.