under section 80 QQB you are entitled to tax deduction of royalty income earned by you for publishing scientific book upto Rs 3 lakhs only
2) obtain certificate from the publishers in prescribed form 10 CCD
3)royalty income should be received by you within period of 6 months of end of previous year or with additional time as granted by RBI
4) in case royalty income is received by you as percentage of sale royalty income then royalty income greater than 15 per cent of sales is to be ignored