When one uses the term back of the book (BOB) stamps he is usually referencing the Scott Specialized Catalog of U.S. Stamps and Covers. It is that catalog that is so arranged that in the front are listed all regular, commemorative and Forever postage stamps, while those following -- literally in the back of the book -- are all stamps that either do not perform the duty of moving the mail, are designated for special service, or are not stamps of the continental U.S.
This arrangement is not common to all stamp catalogs, many of which, like the Stanley Gibbons catalogs list the stamps chronologically, without regard to special service stamps. The everyday collector is usually aware of BOB residents airmail and special delivery stamps, but there are others that may be a surprise or new discovery for him.
Beyond Regular Postage Stamps
Stamp collecting is generally thought of as collecting postage stamps, and it is true that this is the stamp collector’s primary pursuit, but it is nearly guaranteed that he will come upon a stamp not found in the regular postage stamp section of the Scott’s Specialized.
He may buy a postal history item that has a copy of a stamp he collects on the envelope, and it may also feature a postage due stamp. The topical stamp collector may add a piece of postal stationery that shows an item that fits into his collection. It is for these collectors and others that the back of the book section can be valuable.
There are stamp collectors that don’t even collect postage stamps and rely on the listings in the back of the book to guide them. Revenue stamp collecting is a popular area, originally featuring those stamps that the U.S. government released as tax stamps for tobacco, photographs, documents, alcohol and other items.
The tax represented by the stamps helped fund the Civil War.
Some types of BOB stamps and philatelic items:
Official Stamps (Stamps for government agencies and the military)
Postal Stationery (Postcards, envelopes, and aerograms)
BOB stamps can be a fascinating area for the stamp collector, full of an aura of history and further research opportunities.