Complex sentence: McTaggart is known for "The Unreality of Time" (1908), which argues that time is unreal, a work that has been widely discussed through the 20th Century and into the 21st.
Split into simpler sentences: McTaggart is known for "The Unreality of Time" (1908), in which he argues that time is unreal. The work has been widely discussed through the 20th Century and into the 21st.