I don't know how David Mitchell imagined and wrote this book-- it's beautiful, captivating, thrilling in both story and language. My favorite chapters are around the character of Sonmi451 (the sci-fi chapters). The book is existential and soulful at the same time.
haha, I also have my go-to recommendation book which is the "Wind-Up Bird Chronicle" by Haruki Murakami. Little known fact that Murakami is one of Mitchell's idols. If you like Cloud Atlas, you have got to read "The Wind-Up Bird Chronicle".