Blue book

A blue book or bluebook is an almanac, buyer's guide or other compilation of statistics and information. The term dates back to the 15th century, when large blue velvet-covered books were used for record-keeping by the Parliament of the United Kingdom. The OED first records such a usage in 1633. The term has a variety of other meanings. A blue book or bluebook is an almanac, buyer's guide or other compilation of statistics and information. The term dates back to the 15th century, when large blue velvet-covered books were used for record-keeping by the Parliament of the United Kingdom. The OED first records such a usage in 1633. The term has a variety of other meanings.