This is a Sigma Force Novel. Apparently the Sigma Force is a quasi-commando organization operating under the auspices of the DOD. Regardless of whether you have read any of the series, this book is worth reading. It stands alone very well. This would be a great script for an Indiana Jones movie. There are biblical references, strange phenomena and futuristic action. A historic incident leads to a current devastating disease and an archaeologist's children and Sigma Force and responsible to find a cure.
An aspect of the book that I found very interesting was Rollin's commentary at the finish. He provided insight as to the inclusion of factors that made the book more interesting. The addition of Mark Twain, Stanley, Livingston and Tesla was not done randomly. Rollins did a great job in providing background and rationale for much of his work.
The story and plot were excellent. The characterizations were not as satisfying. I guess that Sigma Force fans will know the background of some of the protagonists and will be better able to empathize and identify with them. I just found them a touch too superficial and would have liked more depth on what made them who they are.
Again the story line is excellent and I recommend the book.
This book may have been received free of charge from a publisher or a publicist. That will NEVER have a bearing on my recommendations.