Author: Dan Brown 
Narrator: Paul Michael 
Release Date: September 9, 2025 
Length: 18 hours 45 minutes (unabridged) 
Genre: Fiction, Mystery Thriller 

The Secret of Secrets is the sixth Robert Langdon audiobook thriller, narrated by Paul Michael, where the Harvard symbologist races through Prague, London, and New York to rescue his kidnapped colleague Katherine Solomon and unravel a conspiracy blending noetic science, ancient mysticism, and a shadowy organization that could redefine human consciousness. Brown's signature blend of intellectual puzzles, historical lore, and high-stakes action explores the nature of the mind and hidden truths, with Langdon evading a mythical assailant in a plot that threatens global beliefs.