The Obsidian Chamber by Douglas Preston and Lincoln Child
Hardcover in excellent condition.
Signed by both authors.
Cover price is $36.50, asking $5.00.
From the dust jacket:
After a harrowing, otherworldly confrontation on the shores of Exmouth, Massachusetts, Special Agent A.X.L. Pendergast is missing, presumed dead.
Sick with grief, Pendergast's ward, Constance, retreats to her chambers beneath the family mansion at 891 Riverside Drive - only to be taken captive by a shadowy figure from the past.
Proctor, Pendergast's longtime bodyguard, springs to action, chasing Constance's kidnapper through cities, across oceans, and into wastelands unknown.
And by the time Proctor discovers the truth, a terrifying engine has stirred - and it may already be too late.