The Collaborative International Dictionary of English v.0.48:

Account book \Ac*count" book`\
   A book in which accounts are kept. --Swift.
   [1913 Webster]

WordNet (r) 3.0 (2006):

account book
    n 1: a record in which commercial accounts are recorded; "they
         got a subpoena to examine our books" [syn: ledger,
         leger, account book, book of account, book]