Leonard Gregory Kastle (born December 2, 1929, in New York City) is an American composer, best known for his contributions to classical music and opera. He gained significant recognition for his opera "The Last Temptation of Christ," which reflects his deep interest in the intersection of music and spirituality. Kastle's most notable work is "The Last Temptation of Christ," composed in the 1970s, which, although not widely performed, has been praised for its innovative blend of contemporary classical techniques and dramatic storytelling. His style incorporates elements of minimalism and modernism, characterized by intricate vocal lines and rich harmonic textures. Though not a mainstream figure in the music industry, Kastle's work has influenced a niche audience, particularly in the realm of contemporary opera. His contributions have contributed to the expansion of thematic content in operatic storytelling, exploring complex philosophical and moral questions. Kastle's impact on music, while modest in terms of mainstream recognition, is significant within the context of 20th-century American opera, where he carved out a unique space that resonates with themes of faith, doubt, and the human experience.