Deduction for authors of prescribed Indian language textbooks reduces taxable professional income for specified early assessment years. A new deduction permits a portion of a resident individual author's income from copyright assignments, lump sum payments (including non returnable advances), and royalties for qualifying books to be deducted from total income for the assessment year commencing 1 April 1980 and the four immediately following assessment years, provided the book is a dictionary, thesaurus, encyclopedia or a university prescribed/recommended text and is written in an Eighth Schedule language or a language notified by the Central Government; joint authors are included.