Book profit definition revised to require specified accounting presentation and to add revaluation reserve on asset disposal to taxable book profit. Amendment prescribes that companies prepare profit and loss accounts for computing book profit either under Part II of Schedule VI or under the Act governing companies to which the proviso to section 211 applies, and adds as an add-back to book profit the amount standing in the revaluation reserve relating to a revalued asset on its retirement or disposal if that amount is not credited to the profit and loss account.