Summary assessment protects revenue, enabling assessment and deemed liability for person in charge of goods when taxpayer unascertainable. Summary assessment permits the proper officer, with prior permission of the Additional Commissioner or Joint Commissioner, to issue an assessment order on evidence of tax liability where delay may harm the interest of revenue, including deeming the person in charge of goods to be the taxable person if the taxpayer is not ascertainable; the Additional Commissioner or Joint Commissioner may withdraw such an order within thirty days and direct reconsideration under the reassessment procedure.