If you want a fast paced, well-written book with an interesting (if familiar) concept about time travel, you won't be disappointed with this book. The authors do a good job of postulating what would happen if people from four divergent time periods in southern Illinois were moved back in time to the age of the dinosaurs. One group is from the present, and are the guards and inmates of a maximum security prison. Another group are Cherokee Indians and their U.S. Army escorts from the Trail of Tears, in the mid-1800s. The third group are Spanish Conquistadors under Hernando deSoto. The last group are early aboriginal Indians, the Mounds Indians. The book is entertaining, and there are discussions by physicists who are trying to get to the bottom of what happened that provide enough basic science and physics to make a plausible explanation.
The book rated only thee stars for a variety of reasons. The editing was surprisingly bad. Misspellings were rampant, as were wrong words, omitted words, etc. Love at first sight was also rampant. This got rather tedious, and is more than a bit of a stretch. The cold-blooded murderer/arsonist/armed robber with the heart of gold was also overdone.
These were annoyances more than anything. There were two things that really intruded on the story, and hurt it significantly. The first was the ease and speed with which everyone accepted what happened to them and took it in stride. I found it literally incredible that a group of soldiers and Indians from the 1800s would not be bothered by being thrust back in time 150 million years. Their main concern seemed to be finding a replacement for beef fat in their pemmican. I might have had a few bigger concerns than that.
Finally, the authors should really stop preaching about the evils of "the current administration." Flint is a labor organizer and clearly a staunch Democrat. The authors hate Bush. We get it. Say it once and move on; don't rub our faces in it. What the evils of "the current administration" (the single most used phrase in the book) have to do with people sent back in time 150 million years is a bigger mystery than how they got there. The authors couldn't decide if they wanted to write a science fiction story or a political diatribe. They opted to do mostly the former, with a hefty dose of the latter. It didn't work. I sincerely hope they knock that off in the inevitable sequels. I'll read them, but they will be much better without the political preaching.