Originally published in 1870 by Reverend E.Cobham Brewer, it was aimed at the growing number of people who did not have a college education, but wanted to understand the origins of phrases and historical or literary allusions. The 'phrase' part of the title refers mainly to the explanation of various idioms and proverbs, while the 'fable' part might more accurately be labelled 'folklore' and ranges from classical mythology to relatively recent literature. On top of this, Brewer added notes on important historical figures and events, and other things which he thought would be of interest, such as roman numerals.
Although intended as a comprehensive reference work, early editions of Brewer's are highly idiosyncratic, with certain editorial decisions highly suggestive of the author's personal bias. For instance, a list under the entry for John purported to show the bad luck associated with that name, ending "Certainly a disastrous list of Popes." despite several being described merely as "nonentities". Some entries seem so trivial as to be hardly worth including, and others are almost definitely apocryphal.
Despite this inconsistency, however, the book was a huge success, providing information often not included in more traditional dictionaries and encylopediae. A revised and updated edition was published in 1896, shortly before Brewer died. Since then, it has been continually revised and reprinted, with the 15th Edition being the first to make truly wide-scale changes to the content. The most recent version is the 16th Edition, published in May 2000, and edited by Adrian Room.
The "Revised and Updated Edition" from the 1890s is now in the public domain, and web-based versions are available from sites such as Bartleby and Bootleg Books.