Theme and Variations is a musical form that begins with a main theme, which is then altered in several ways throughout the piece. Each variation maintains the essence of the original theme while introducing changes in melody, harmony, rhythm, or instrumentation. This allows composers to explore different musical ideas while keeping a recognizable foundation. This form is commonly found in classical music and is often used by composers like Wolfgang Amadeus Mozart and Ludwig van Beethoven. The variations can range from subtle modifications to dramatic reinterpretations, showcasing the creativity and versatility of the composer while engaging the listener.