A ledger is the main book or computer file to record and totalize economic transactions measured in terms of one currency unit of account by account type, with debits and credits in separate columns and an initial monetary balance and final monetary balance for each account.
In accounting and bookkeeping, a ledger is a book (or record) for collecting chronological data from a magazine's transactions and arranging entries by account.
The ledger provides the transaction history and the current balance in each accounting system account, throughout the accounting period. At the end of the period, ledgers are, therefore, the authoritative source of data for the preparation of a company's financial accounting reports, including the profit and loss account and the balance sheet.