Special Purpose Books – A First Look

Think about your own diary. You might jot down everything in one place – expenses, friend's birthdays, to-do lists. But when you need to find "how much I spent on food last month," you have to flip through every page. That's messy.

Now imagine a shopkeeper. Every day, hundreds of transactions happen: selling goods, buying stock, paying rent, receiving cash from a customer. If the shopkeeper wrote everything in one book, finding a single mistake would take hours. Worse, the book would be a jumble of unrelated entries.

That's why accountants use Special Purpose Books – separate notebooks for each type of transaction. Instead of one diary, you have a "Sales Diary," a "Purchase Diary," a "Cash Diary," and so on. Each book records only one kind of event, making the whole system clean, fast, and hard to mess up.

What Exactly Is a Special Purpose Book?

A Special Purpose Book (also called a Subsidiary Book) is a book of original entry – the first place a transaction is recorded – that is reserved for a single class of transactions. Instead of dumping everything into one Journal, you use:

• Sales Book – only credit sales of goods
• Purchase Book – only credit purchases of goods
• Cash Book – only cash and bank transactions
• Sales Return Book – only goods returned by customers
• Purchase Return Book – only goods returned to suppliers
• Journal Proper – the leftover transactions that don't fit anywhere else (e.g., opening entry, rectification, transfer entries)

Why Does This Matter?

Three reasons, and they are big ones for any exam or real business:

1. Division of labour – One person handles sales, another handles purchases. No single person is overloaded.
2. Speed – Recording a credit sale in the Sales Book takes seconds because you don't have to write "Sales Account Dr, Customer Account Cr" every time – the book's format does that for you.
3. Error detection – If the total of the Sales Book doesn't match the total of the Sales Account in the ledger, you know exactly where to look.

Accounting Treatment – The Debit/Credit Logic

Here is the key rule: Every Special Purpose Book is a journal in disguise. Each book has a built-in double-entry logic. When you record a transaction in a Special Purpose Book, you are implicitly doing a journal entry. Later, the totals are posted to the ledger.

Let's take the most common ones:

1. Sales Book (Credit Sales of Goods)

• Debit: Customer's Personal Account (the buyer owes you money)
• Credit: Sales Account (revenue earned)

But in the Sales Book, you don't write "Dr" and "Cr" for each line. You just list the customer's name, invoice number, and amount. At the end of the month, you total the book and post:

• Debit the total to Sundry Debtors Account (in the ledger)
• Credit the total to Sales Account

2. Purchase Book (Credit Purchases of Goods)

• Debit: Purchases Account (expense/inventory)
• Credit: Supplier's Personal Account (you owe them money)

At month-end:

• Debit the total to Purchases Account
• Credit the total to Sundry Creditors Account

3. Sales Return Book (Goods Returned by Customers)

• Debit: Sales Returns Account (contra to sales)
• Credit: Customer's Personal Account (reduce what they owe)

Month-end posting:

• Debit the total to Sales Returns Account
• Credit the total to Sundry Debtors Account

4. Purchase Return Book (Goods Returned to Suppliers)

• Debit: Supplier's Personal Account (reduce what you owe)
• Credit: Purchase Returns Account (contra to purchases)

Month-end posting: …