This book is a comprehensive commentary on the Reassessment provision under the Income-tax Act, as introduced by the Finance Act, 2021. It features an exhaustive discussion on both fundamental concepts and issues arising under the new law of reassessment combined with essential commentary on statutory provisions and the jurisprudence. It also includes cross-references to other chapters wherever implications need to be understood entirely to assist the reader. The objective of this book is as follows: [Amendments made by the Finance Act 2021] To provide a general idea about the amendment through Finance Act, 2021 in the provisions relating to reassessment [Insight into Provisions] To provide an insight into various provisions through a simple and understandable explanation [Condition for Deeming Provisions/Procedure] To highlight the conditions under which deeming provision of section 148 can be applied, or procedure contained in section 148A can be followed [Case Laws under the Old Law] To highlight to what extent propositions upheld by the Courts under the old law can be applied under the new law [Revision u/s 263 in Reopened Cases] To highlight the circumstances under which revision u/s 263 in reopened cases can be done [Penal Provisions] To highlight the circumstances under which penal provisions in relation to escaped income can be invoked.