These bound collections of paper provide a method for creating duplicate records of transactions. Typically, the original copy is given to the customer, while the carbon copy remains within the book for the business’s record-keeping. An example would be a service provider, such as a plumber, issuing a record of payment to a client after completing a job. The client receives the original receipt, and the plumber retains the duplicate in their book.
The value of such systems lies in their simplicity and reliability. They offer an immediate, physical backup of transactions, reducing the potential for data loss associated with electronic systems. Historically, these books were essential for businesses without access to computers or reliable electricity. Even today, they provide a tangible method for tracking income and expenses, particularly useful for small businesses or individuals who prefer manual record-keeping.