The book is short (which makes it good for reading when I’m in charge of the two kids) and touches very briefly on a host of scripts and the variety of languages that employ them, occasionally going into some depth, but more often just exemplifying. Those parts that I found most interesting and that related to English were a discussion of the use of italics in Latin scripts and a taxonomy of script capabilities.
"Only a few systems of writing – Latin, Greek, Cyrillic, Armenian – have developed bicameral form, but every script that is heavily used develops multiple styles… This has happened with the brittle and fluid forms of the Latin lower case, which are known as roman and italic. Latin script is unusual, however, in the intimate way it has come to exploit the differences between the two."Apparently this began in the 16th century with mathematical notation and then expanded to indicate the names of ships, books, and foreign languages.
(Japanese is one of the few scripts that does something similar, except that it does it the other way round, with the cursive ひらがな (hiragana) script being the standard and the angular カタカナ (katakana) script being used for foreign words, among other things.)
Bringhurst introduces his 4-way taxonomy of script capabilities late in the book. Where DeFrancis and others tend to classify scripts as logographic, syllabic or alphabetic, Bringhurst has semographic, syllabic, alphabetic, and prosodic. Standard staff-music notation would be an example of prosodic script, as would most English punctuation. Bringhurst wisely allows for a given language to employ a script or scripts that fall into more than one category. For example, English recruits the semographic Arabic numerals, prosodic punctuation, and alphabetic Latin scripts. In fact, he points out that Latin script can be syllabic, as in FBI, or semographic, as in MMVI (which, BTW, doesn’t seem nearly as grand as MCMLXXXIV or other late 20th century dates).