Explorations in Typography is a vast collection of typesetting examples. Page after page, a brief article by Erik Spiekermann has been set in hundreds of ways in hundreds of typefaces, creating an extended visual taxonomy of typesetting that allows you to learn by looking.
Beautifully printed and bound, with complete type specifications on every page and examples set in hundreds of faces (many from the FontFont library), the book is an extensive resource of typesetting ideas.
The second edition has been revised and expanded to include more typesetting examples and more typefaces as well as a visual index of page layouts and grids. This edition also features the writing of Stephen Coles who composed all new typeface descriptions and an index of alternates for each that are low-cost or free for educational use.
Available on http://www.explorationsintypography.com