Judicial review is a legal concept that refers to the power of judges to determine the constitutionality of laws and actions of government officials. In other words, it allows courts to decide whether or not certain decisions made by legislative bodies or executive branches are in accordance with the law and the country's highest governing document - usually a constitution. This means that if an individual believes their rights have been violated due to an unconstitutional law or action, they can bring their case before the court for review. If the court finds the law or action to be unconstitutional, it may declare it null and void, meaning it no longer has any legal effect. Judicial review is a crucial mechanism in ensuring that government powers are exercised within the limits of the law, protecting individual rights and liberties.