Books like Skulls and keys by David Alan Richards

Dan Brown’s thriller follows symbologist Robert Langdon and cryptologist Sophie Neveu as they race through Paris to solve a murder at the Louvre, uncovering a conflict between the Priory of Sion and Opus Dei over a controversial religious secret.

The Lost Symbol follows Harvard symbologist Robert Langdon as he unravels a conspiracy in Washington, D.C., using Freemasonry and cryptographic puzzles to uncover hidden truths.

Priestess Pyrre Lakatur must kill a list of ten targets—including the one she loves—within ten days to prove fidelity to the God of Death and avoid being given to the deity herself.

When Junior High detective Sammy Keyes ventures into a graveyard on Halloween, she and her friends uncover a perplexing mystery of missing people, human skulls, and a sinister embalmer, all while their school throws in its own tricks and treats.

"I very much need to be dead." These are the chilling last words left by a man who had everything to live for but took his own life. In the void that remains stands his widow, FBI agent Jane Hawk, surrounded by questions destined to go unanswered unless she does what all the grief and fury inside her demand: Find the truth, no matter what. People of talent and accomplishment, people seemingly happy and sound of mind, have recently been committing suicide in surprising numbers. A disturbing pattern is beginning to emerge. Jane is determined to give up everything to find out why. And if that means going rogue and becoming America's Most Wanted, then so be it. Those arrayed against her are legion, and devoted to protecting something profoundly important-or terrifying-enough to exterminate any and all in their way. But Jane is as clever as these enemies are cold-blooded, as relentless as they are ruthless. And she is driven by a righteous rage they can never comprehend. Because it is born of love.

When teenage singer Leah Wakefield vanishes, Detective Wesley Peterson suspects the same kidnapper who took little Marcus Fallbrook in 1976. As Marcus inexplicably returns from the dead and an arctic excavation uncovers new clues, the mystery deepens.

When a clandestine group of scientists called the Immari unearths relics from an ancient enemy, humanity faces certain extinction. Only a genetics doctor and a secret agent can race against time to discover the fabled Atlantis Gene and halt the catastrophe.