The day book or journal is the familiar two-column form, the left-hand column being used for debits and right-hand column for credits. The _cash book_ has two columns on each page, and these columns are used to separate the items affecting personal accounts, which are to be posted, and all other items, none of which are posted. See illustration. The _ledger_ is the same form as used in the double entry method. The _order book_ is usually the regular two-column journal form. In retail businesses it is used as a principal book, transactions being posted from it to the ledger. Sometimes the first column is used for prices, the extensions being made only when the order is filled. The _bill book_ is quite essential in a single entry set for the reason that no Bills Receivable and Bills Payable accounts are kept in the ledger. =4. Rules for Debit and Credit.= The rules for debit and credit are the same in single entry as in double entry, except that no debits and credits are recorded which do not effect persons or cash—when a cash account is kept. Briefly, these rules applying to single entry are: _Debit the person_ When he receives anything of value; When you pay him cash. _Credit the person_ When you receive anything of value; When he pays you cash. _Debit cash_ When you receive it. _Credit cash_ When you part with it. =5. Posting.= There is no difference between posting to a single entry ledger and one kept by the double entry method. However, the only accounts posted are personal accounts, and the ledger shows merely how much money the business owes to persons and how much money persons owe the business. A single entry ledger does not show the amount of our notes outstanding, or the amount of other persons' notes held by us. This information can be found only in the bill book. The ledger does not show the value of merchandise purchased or sold, expenses of the business, nor the amount of our investments in land, buildings, or other forms of property. =6. Proprietor's Account.= A proprietor's investment or capital account is kept in single entry just as it is in double entry. This may or may not include withdrawals. They may be recorded in a personal or private account, in which case the proprietor's account will exhibit the net investment in the business.