Assessment of Undisclosed Income - search triggers block-period assessment and abates other proceedings. A search or requisition compels the Assessing Officer to assess the total undisclosed income for the block period; pending assessments for tax years within that block period abate on initiation, notices issued during the initiation-to-order period abate on issue, and references under section 166 similarly abate. Subsequent searches require completion of any pending assessment first, with a minimum three-month period allowed for the later assessment if necessary. Annulment of an assessment or order under section 294(1)(c) revives abated proceedings upon receipt by the Principal Commissioner or Commissioner, subject to cessation if the annulment is set aside. Income of the year of the last search is assessed separately, and block-period undisclosed income is taxed as block-period income at the rate in section 192.