Book keeping is an unsystematic method of recording transactions.It is observed, that many businessmen keep incomplete records because of the following reasons : 

Preparation of the profit and loss account cannot be prepared through the information assembled through the single entry system. This means that this system cannot help the organization to determine its financial position because there is no provision to make adjustments.

On the other hand, the double entry system of recording financial transactions of the organization is useful in the preparation of trading profit and loss accounts as adjustments are made at the time of preparing final accounts.

In single entry system, incomplete records are maintained while in double entry system complete recording of transactions is there. In single entry system comparison between two accounting periods is very difficult.

The dual aspect concept states that every business transaction requires recordation in two different accounts. This concept is the basis of double entry accounting, which is required by all accounting frameworks in order to produce reliable financial statements.

A single entry book-keeping system or single-entry accounting system is a method of bookkeeping relying on a one sided accounting entry to maintain financial information.

In single entry system following things are prepared:

1. Cash book - to record all cash transaction

2. Customer's book - to record balances of debtors

3. Day Books - in which all day to day transactions or activities are recorded

4. Statement of profit and loss to arrive at profit or loss.

5. Statement of affairs to arrive at closing capital at the year end.

As Profit or loss under single entry system is ascertained by the difference between Closing and Opening Capitals it make convenient for small traders to follow single entry system due to following features:
a) Hassle free
b) no need for maintaining books of accounts
c) special knowledge of double entry system is not required.

Suppose Opening Capital (i.e capital on the 1st day of financial year) is Rs. 50,000 and Closing Capital ( i.e capital on the last day of financial year ) is Rs. 70,000. the resulting difference is more by Rs. 20000 indicating a positive increment in capital called Profit.

Normally Single entry system is maintained by small traders as it do not require special set of book-keeping and expert accounting knowledge. Hence, it becomes hassle free for traders to ascertain their profit of loss earned by the business through single entry system.

A system were Profit or loss earned by the business  is based on the difference between its Opening and closing capital. is called Single entry system
In order to find the  capitals , Statement of affairs are prepared which are based on an equation Capital = Assets - Liabilities
Hence, basic accounting aspects of debit and credit are not followed.

Under Single entry System only personal accounts and cash A/c are opened. 

Under single entry system Books of accounts are not maintained hence, Trial Balance is not Possible to Prepare.

Profit or loss earned by the business under single entry system is based on the difference between its Opening and closing capital.
To ascertain this capital Statement of affairs are prepared.

Single Entry System of Accounting, also known as Accounting from Incomplete Records, is a non-standard and non-scientific system of accounting. This system is adopted by small businessmen as they do not have enough capital and expertise to employ the standard double entry system of accounting in their business.

Sole proprietorship is type of enterprise that is owned and run by one natural person and in which there is no legal distinction between the owner and business entity. The owner is in direct control of all elements and is legally accountable for the finances of such business and this may include debt, loans, loss, etc.

For a Sole Proprietor, income tax is not an expense incurred to generate revenue hence it is not treated as an expense to be paid out of profits. In this case, income tax is treated as a personal expense resulting in drawings from the business concluding to a reduction of capital.