Subsidiary Book

Some transactions like credit purchase, credit sales, return of goods purchased, return of goods sold, bills receivable, bills payable, cash paid and received etc are occurred so many times in a day. To enter such repetitive transactions in a journal consumes more labor, time and money. When the business transactions are numerous, one person may not be able to maintain all the books of accounts himself. Recording of all the books of accounts himself. Recording of all transactions in a journal can not avail the classified information of a particular transaction, say information about purchase, information about sale etc. Thus, transactions relating to one particular head are recorded in a separate book. In other words, a separate book is maintained to record the similar transactions which are called "Subsidiary Books". It is also called as "Special Journals" or "Sub-Division of Journal" or "Day Book".

In the modern book-keeping, the repetitive or routine transactions are recorded in subsidiary books and the occasional transactions which occur in a long time interval are recorded in a general journal. Purchase Book, Sales Book, Sales Return Book, Purchase Return Book etc are some subsidiary books.