Question: is the movie the lake house based on a book

Answer: No, The Lake House is a 2006 American romantic drama directed by Alejandro Agresti and starring Keanu Reeves, Sandra Bullock and Christopher Plummer. It was written by David Auburn. The film is a remake of the South Korean motion picture Il Mare (2000). The story centers on an architect living in 2004 and a doctor living in 2006. The two meet via letters left in a mailbox at the lake house they have both lived in at separate points in time; they carry on correspondence over two years, remaining separated by their original difference of two years.