The Sales Ledger maintains records of transactions between your business and individual Customers.
When you setup a new Customer you are creating a Sales Ledger Account. This account is automatically updated when you enter a Sales Invoice or make an entry in the Sales Book. It is also automatically updated when you record in the Cash Receipts Book details of receipts from a customer and any discount given.
Looking up the Sales Ledger account for a Customer will show you a list of invoices and credit notes you have sent to that Customer, payments received, details of any adjustments made to the account (e.g. for discount given) and the balance owed by the Customer.
Information in the Sales Ledger can be accessed in a variety of ways; examining a Sales Ledger Account on screen and displaying/printing reports and Debtor Statements.