Cash Book – A subsidiary book and principal book of accounts
All the cash transactions are recorded first in the cash book. It is therefore a subsidiary book. When cash book is maintained, there is no need for preparing cash account and bank account in the ledger because in the cash book cash receipts and cash payments are compared and the cash and bank balances at the end are arrived at. Thus, it serves as a ledger account also. Hence, the cash book, unlike any other subsidiary book, is both a subsidiary book and a principal book.