Complex sentence: The book was immediately successful, selling more than 1 million copies in the US, as were his follow-up works, "The Art of Seduction" and "The 33 Strategies of War".
Split into simpler sentences: The book was immediately successful, selling more than 1 million copies in the US. His subsequent books shared similiar success including "The Art of Seduction" and "The 33 Strategies of War".