When does Sigma Force return?

James Paul Czajkowski, aka James Rollins, is an American veterinarian and writer of action-adventure/thriller and mystery novels. Under the pen name James Clemens, he has also published fantasy novels, such as Wit'ch Fire, Wit’ch Storm and Wit”ch War. Rollins was inspired by Jules Verne and H. G. Wells, whose works he used as a springboard.