Complex sentence: His most popular work was "The Clockwork Muse" (1990), in which he argued that all artistic development over time in written, visual and musical works was the result of a search for novelty.
Split into simpler sentences: His most popular work was "The Clockwork Muse" (1990). Martindale argued that all artistic development over time in written, visual and musical works was the result of a search for novelty.