Rulemaking power under the Expenditure-tax Act enables procedural rules, retrospective effect and parliamentary scrutiny for tax administration. Section 31 vests the Board, under Central Government control, with rulemaking authority by notification to implement the Expenditure-tax Act, specifying subjects such as room charge determination, conversion of foreign exchange payments, forms and verification for returns, notices and appeals, and other prescribed matters. The first exercise may provide retrospective effect from the Act's commencement, and all rules must be laid before Parliament for review, with Parliament empowered to modify or annul rules without affecting prior validity under those rules.