Explanation:

A ledger is the principal book or computer file for recording and totaling economic transactions measured in terms of a monetary unit of account by account type, with debits and credits in separate columns and a beginning monetary balance and ending monetary balance for each account.

Business transactions are first entered in Journal or Special Purpose Subsidiary Books. The next step is to transfer the entries to respective accounts in ledger. In other word, all entries recorded in journal or special purpose subsidiary books are classified and in order to ascertain the position of a particular account, all transactions relating to that particular account are collected at one place in the ledger. In short, a ledger is a book which contains all accounts of the business enterprise whether Real, Personal or Nominal. Ledger is called the "Principal Book'. It is also called the book of final entry because the transactions which are first entered in journal or subsidiary books are finally incorporated in the ledger.