As a longtime fan of Dan Brown's thrillers, I've dug deep into his bibliography to uncover his works involving angels and demons. His most famous novel is undoubtedly 'Angels & Demons,' the first book in the Robert Langdon series, which revolves around a secret society, the Illuminati, and a race against time to prevent a catastrophe in Vatican City. While 'Angels & Demons' is his only book with 'angels' and 'demons' in the title, themes of religious symbolism, secret societies, and the battle between science and religion permeate many of his other works.
For instance, 'The Da Vinci Code,' the sequel to 'Angels & Demons,' also explores similar themes but doesn't explicitly focus on angels or demons. 'Inferno,' another Langdon novel, delves into Dante's depiction of hell but doesn’t center on angels. So, if you're looking for books specifically about angels and demons, 'Angels & Demons' stands alone in Dan Brown's catalog. That said, his other novels share the same thrilling blend of history, conspiracy, and religious intrigue that made 'Angels & Demons' a global phenomenon.