This guide to punctuation, written in 1963, has become a curiosity with the passage of time. Despite its often informal style, this book was probably a useful and reliable reference during the era in which it was first published (my copy was printed in 1971). However, language often evolves more quickly than we realize, and a significant portion of this text has become outdated. This book's main appeal is to the small number of people who are hardcore grammar nerds and might find it interesting to see how the English language has changed over time.
Some of it is outdated and should be ignored, but on the whole a fairly good look at punctuation and its rules and quirks. Useful to brush up a bit on some proofreading skills as I was doing.