Stanley Morison is always a pleasure to read. He had enormous influence on twentieth centry type founding, and an encyclopedic knowledge of the history of type. It's a fascinating subject, partly because type design, more than just about any other art, is vividly aware of its own past, and is inextricably bound up with commerce.
Up to about p.38, this book keeps the promise of its title, the search for a "scientific" classification system (a teeth-gritting misuse of the word). It discusses the history of letter forms as they appeared in cast type. The second essay also discusses one strand in the tapestry of calligraphy's history.
After that point, however, Morison seems to switch gears. Gradually at first, he mentions earlier commentators on typography. By the end of the first essay, the topic is wholly the history of such commentaries, making this a history of typographic histories. It's a great starting point for someone about to embark on an academic study, but of limited use to the practicing typographer.
It's brief, though, and still interesting to any reader wanting to know more about the typography's history. It just doesn't say a lot about the letter forms themselves.