The simultaneous publication of two large, multiauthored books devoted to blood platelets is a landmark in hematology. In 1970, when I completed my training, I changed my research focus from red cells (the interest of my mentors) to platelets. Very little was known about platelets at that time; it was an open field for a beginning investigator. What a difference three decades have made. These two books represent the progressive narrowing of focus that is essential to the description of expanding knowledge. When I was beginning my career, books in this subspecialty were simply titled Hematology; later, books on hemostasis and thrombosis appeared; now, with these books, the focus has narrowed further, to platelets. The beauty of these two books is not just their focus but also their elegant presentation and breadth of topics. The books have similar content and a nearly parallel design. Both begin with enjoyable and instructive historical perspectives that present accounts of the evolution of our knowledge about platelets written by authors whose productive careers have spanned this evolution: Barry Coller in the Michelson book; Fraser Mustard, Raelene Kinlough-Rathbone, and Marian Packham in the book edited by Gresele et al. The latter book also concludes with an additional historical perspective by Gustav Born.