In the work "The Termination of the Indefinite Employment Contract," a critical presentation and an initial approach are made regarding the changes brought about by the recent Law 4808/2021 in a series of provisions concerning the termination of the indefinite employment contract, particularly regarding the burden of proof for the reason of nullity and the consequences of nullity. The book, which complements the publication of the monograph "The Termination of the Employment Contract" (2020), aspires to be a useful tool for legal theory and practice by identifying and highlighting the critical issues that have arisen with recent legislative changes.