Summary assessment powers permit expedited tax assessment to protect revenue when delay would prejudice collection. Summary assessment allows the proper officer, with prior senior authorisation, to assess tax liability immediately when evidence arises and delay would harm revenue; if the taxable person is unascertainable in goods cases, the person in charge is deemed the taxable person liable for assessment and payment. The senior officer or the taxpayer may trigger review, and the senior officer may withdraw a summary order and pursue reassessment under the regular procedural framework.