A Finalizer is a special method in programming, particularly in languages like C# and Java, that is used to perform cleanup operations before an object is removed from memory. It allows developers to release resources, such as file handles or network connections, that the object may be holding. Finalizers are automatically called by the garbage collector when it determines that an object is no longer in use. However, relying on finalizers can lead to performance issues and unpredictable behavior, as the timing of their execution is not guaranteed. Instead, developers are encouraged to implement the IDisposable interface or use using statements to manage resources more effectively and ensure timely cleanup.