Ada or Ardor by Vladimir Nabokov

Set in an alternate universe where Earth is known as "Antiterra," the novel follows the lives of Ada and Van, two wealthy siblings who fall into a passionate and incestuous love affair. Their relationship evolves over a span of 70 years, as they navigate through family secrets, personal tragedies, and the complex nature of time. The book is a blend of romance, science fiction, and philosophical exploration, all told through the author's signature wordplay and intricate narrative style. The 404th greatest book of all time