Revenue (Sales) is the top-line income from goods or services sold. Recognize revenue when control of goods/services transfers and performance obligations are satisfied. Measure at transaction price, allocating to distinct obligations. Present gross sales and subtract sales returns, discounts, and allowances to report net sales. Record deferred (unearned) revenue for advance payments. Revenue classification: product sales, service income, rental and royalty income. Accurate revenue recognition affects gross profit, operating profit and taxable income, and must follow applicable accounting standards (e.g., IFRS 15, ASC 606)