Summary assessment powers enable expedited tax determination based on evidence to protect revenue and secure unpaid liabilities. Summary assessment permits a proper officer, with prior approval of the Additional/Joint Commissioner, to determine tax liability without calling the taxable person, provided the action is based on evidence and intended to protect revenue; if the liable person is unascertainable for goods, the person in charge is deemed taxable. Withdrawal of a summary order may follow on application by the person or suo moto by the Additional/Joint Commissioner, after which regular assessment proceedings and prescribed notices must be initiated.