Two physicists, a paleontologist, a security guard and a dog walk into a bar ... OK, not really. But two physicists, and their dog, are working on an experiment in a sealed vault in a small university in South Dakota, when odd items begin appearing inside the vault, then disappearing. They begin to suspect that they found something much more earth-shaking than what they sought, and invite a paleontologist on staff to help them figure it out. A security guard catches the unauthorized staff-member there but, before he can do anything about it, everything blows up, with startling effects on the four people and the dog.

The quartet ends up in the same location, but 65 million years earlier, in the Cretaceous period, when mammals were beginning to get some numbers and variety, dinosaurs were dwindling, the Rockies were big, rolling hills, the middle of North America featured vast jungles and an inland sea, and humans were 60 million years into the future. The physicists use a complex equation to calculate where they have to be, at a certain time, to stand any chance of "reverting" back to their time of origin, just as the items that appeared in the vault had reverted back to the past.

Thus launches an epic journey across a thousand miles of harsh, dangerous territory, with only their wits and creativity to help them survive. Their journey is long and loaded with peril, plus they encounter several surprises, not all of which are unpleasant.

Meanwhile, back at the ranch, er, university, the police, led by Chief Sharon Earles, who reminded me of the police chief in the movie Fargo (ya, you betcha), had to figure out what happened to the four people and a dog that have vanished. Well, actually, four-and-a-half people, as a second security guard was cleanly sliced in two by the phenomenon that caused the disappearances. Is it murder? Did the missing people just leave, or were they abducted? Chief Earles calls in two more physicists to help solve the riddle --- or will they end up helping themselves?

This wonderful novel combines an adventure story -- part Jurassic Park by Michael Crichton, part Dinosaur Summer by Greg Bear -- along with a crime or detective mystery, with plenty of scientific tidbits sprinkled throughout. The science part emphasizes, in descending order of prominence, paleontology, physics and geology.

The writing here is generally excellent, with vivid descriptions of settings and great character development. There is plenty of action and suspense as well. However, the story does get a little slow in spots, right after the characters translocate to the Cretaceous period, which, by the way, immediately followed the Jurassic period, whose critters were made famous in Jurassic Park (book and movie). The pace does pick up quickly, and then remain quick and steady after that, and those few slow spots did not detract from the reading experience, for me.

Who will like this book? Anyone who enjoyed Jurassic Park and/or Dinosaur Summer would, and this one has a bit more scientific meat on its bones. Anyone who enjoys a good adventure story, with pieces of detective work, education on several scientific fields and even a touch of romance mixed in, should love this. I know enough about paleontology, physics and geology to enjoy this book, but experts or amateur aficionados in any of those areas might find a flaw or two.

Who will not like this book? If you are squeamish, you might be put off by a few scenes. If you are strong in your beliefs of opposing the theory of evolution, I suggest you avoid this novel.

Cretaceous Dawn, by brother-and-sister team Lisa M. & Michael S.A. Graziano, has also been published as Hell Creek: 65 Million Years in the Past, the Journey Begins.