Some of my favourite episodes of any Star Trek series are when they go back to a past era of Earth.
In this book Ward takes aspects of DS9's Little Green Men plus Carbon Creek from Enterprise and made it his own by following the lives of two human investigators searching for proof of alien contact on behalf of the US government. They work from the first days of the Majestic 12 organization and through Project Blue Book.
I'd never heard of Majestic 12 (also know as MJ-12) and that's because it lives in the world of conspiracy theorists but Project Blue Book was real. I also remember watching a TV show called Project U.F.O that followed two Project Blue Book investigators. I was always disappointed that swamp gas seemed to be the answer behind most of the UFO sightings. To be fair, Blue Book debunked most sightings it investigated. Nine-year-old me really, really wanted to meet an alien. In any case, you gotta love an author that can seamlessly blend fact and fiction to create, well, better fiction.
The story did bounce back and forth between Kirk's Enterprise and the Earth from the 40's to the 60's and made my head swim a bit. Time travel stories have a way of spinning out of control if the author is not careful. I did appreciate some of Kirk's musings on how time travel gave him a headache.
All in all the book was very entertaining and I highly recommend it. As long as you have a passing knowledge of Star Trek you'll be fine.