If you only read one book on punctuation, it should be On the Mark: A History of Punctuation from Ancient Egypt to the Emoticon by Florence Hazrat, which was published last week. Previous books have covered the history of punctuation in Western literature (Pause and Effect by M.B. Parkes), and the history of English punctuation (Making a Point by David Crystal), though On the Mark is the history of the subject with the widest scope. (“The first global history of punctuation”, according to its publisher.)
Hazrat discusses the ancient origins of punctuation and its development not only in English but also in other European languages and even in Arabic. She cites some fascinating examples, including an early use of emoticons in the Polish newspaper Kurjer Warszawski (‘Warsaw courier’) that slightly predates a more famous example from Punch magazine. (The Polish emoticons were published on 5th March 1881, and those in Punch appeared twenty-five days later.) The book also includes an excellent bibliographic essay.