Powers of tax authorities to compel discovery and impound documents enable investigations even without pending proceedings. Specified income-tax authorities possess civil-court-equivalent powers to order discovery, enforce attendance and oath, compel production of books and documents, and issue commissions; certain investigative officers may exercise these powers on suspicion of concealed income even without pending proceedings, and notified authorities may use them for inquiries under international tax agreements. Authorities may impound produced records subject to rules, but Assessing Officers must record reasons for impoundment and obtain higher approval to retain records beyond fifteen days.