Summary assessment enables immediate tax assessment to protect revenue interests where delay risks loss, subject to higher officer review. A proper officer, with prior authorization from an Additional or Joint Commissioner, may conduct a summary assessment and issue an assessment order where evidence indicates tax liability and delay may prejudice revenue; if the taxable person is unascertainable for goods, the person in charge is deemed the taxable person. The senior officer may withdraw an erroneous summary assessment on application or on motion and then proceed under the ordinary reassessment procedures.