This is the first book of Rollins that I read and I have to say I loved it so much that it convinced me to read his other books as well. This is a SIGMA Force novel. Here is what the back of the book says... "Lady Kara Kensington's family paid a high price in money and blood to found the gallery that now lies in ruins. And her search for answers is about to lead Kara; her friend Safia al-Maaz, the gallery's brilliant and beautiful curator; and their guide, the international adventurer Omaha Dunn, into a world they never dreamed actually existed: a lost city buried beneath the Arabian desert, where something astonishing is waiting. A covert government operative hunting a dangerous turncoat - his former partner - is being drawn there as well. But the many perils of a death-defying trek deep into the savage heart of the Arabian Peninsula pale before the nightmare to be unearthed at journey's end - an ageless power that lives and breathes, an awesome force that can create a utopia ... or tear down everything humankind has built over millennia of civilization."