Ian and Vicki Utz are married spies who really know how to love - their kids, their friends and aviation. They especially know how to romance each other.

Besides being CIA spies, both are top Air Force pilots. "Mach 6" is their plum assignment after an extraordinary encounter told in the book, "Complexity."

Venerable CIA agent Oliver Bakker, whose past exploits are still far above Top Secret, finds himself cleverly framed for murdering his best friend. If he goes to prison, he'd last a month, because his mortal enemies control prisons. Moreover several governments might fall. He escapes and fakes suicide, then reads he was acquitted after all. Oh well, dead for a while, he can operate more freely, protecting those he loves.

Nearly everyone in "Mach 6" is a spy, a counterspy or a saboteur. They are swirling around the most secret and desired research on earth, a Mach 6 aircraft that Ian and Vicki are developing at Area-51. Most nations want the aircraft. Some would wage war to get it, or its plans.

A shadowy conspiracy of twelve, with tentacles squeezing the highest levels of many governments covets the technology most of all. Competing agents are trying to create, protect, steal and destroy what will become a multi trillion dollar industry - the secret of Mach 6 flight.

There is an unobtainable material wryly named Non-Existium because it is a stretchy aircraft skin that will withstand the white heat of Mach 6 air friction. It must be invented.

Even if it can be made, how does one keep Mach 6 air from blowing out the flame in any jet engine that can also run both at takeoff and landing speeds? Then what about the four undiscovered speed barriers between Mach 1 and Mach 6, each potent enough to rip an ordinary plane to shreds?

This book has given NASA ideas. Recently, they trotted out a Gulfstream using hingeless flaps like the Spectre in this novel. In the 21st century, who really needs an aircraft tail or windows? How do you prevent landing gear door hinges or aileron hinges from burning off?

What kind of fuel has the energy to power the craft for 90 minutes, flying from San Francisco to Paris, Moscow, Beijing or Tokyo?

And how do two top spies / pilots keep their loved ones secure, healthy and warm, while the world's most potent adversaries focus everything on destroying them?

How, indeed, when those enemies might even have private nukes on US soil?

It'll be interesting to find out how they can succeed, if they can succeed.

If they do, in this third volume of the Mach Books series (1)Audaz, (2)Complexity, (3)Mach 6, (4)The Room bOmb. There will be many more.

Well, that let the cat out of the bag They do survive "Mach 6" to reappear in "The Room bOmb," already published. Do enjoy a tale as strong and twisty as a hawser, twisted of ropes, twisted of strings, twisted of threads, twisted of black widow spider webs.

If you're a spy or have been one, -- if you've experienced the kind of romance Ian and Vicki Utz know so well, -- if you've flown high-Mach aircraft at the edge of space, -- if you have worked in secret at Area-51, -- if you've been at the boardroom levels of a team pioneering a whole industry from scratch, you'll find 'Mach 6' eerily familiar.

If you have not, then 'Mach 6' is a first-person spree into those turbulent worlds, where at least Some things are as they seem.

The trouble with espionage is that spies never seem to know which things are which.

Mach 6: Spectre Spy - heftet, Engelsk, 2012