John Puller is an investigator with the CID, the Criminal Investigative Unit based in Virginia. An experienced and accomplished soldier, Puller is sent to West Virginia to investigate the suspicious death of a DIA agent. Upon arriving in West Virginia, the mystery deepens further as Puller investigates DIA agent's death as that of his entire family. As the body count piles up, Puller teams up with local cop Samantha Cole in a race to find answers and uncovers an unexpected deception bigger than one man can possibly handle alone.One of the most impressive elements of this book is Baldacci's character dialogue. Staccato, fast paced, and completely authentic, the dialogue adds dimensions to the characters, situations, and places with flawless execution. Puller is a rough, ready and patriotic Army man who served six tours in Afghanistan and carries his fair share of scars and medals to prove it. You would expect a macho unstoppable machine without emotion but Baldacci does an excellent job of walking the line and creates a character with just the right mixture of humor, justified bravado based on experience and skilled training honed to a razor edge, with a nice touch of humanity. Puller has a soft spot and it shows through like a brief ray of sunshine, making him an extraordinarily likable character.Sergeant Samantha Cole is the perfect counterbalance to Puller. A feisty, seasoned cop who gives as good as she gets from Puller, she can stand her own and then some. The verbal banter between them is a joy to experience as the story evolves. A host of other characters complement the dynamic duo and provide layers of intrigue and mystery throughout. The language is crisp, clear, and exacting in its execution.There are times when you read a book and understand immediately why a writer is a bestseller. Baldacci is one of those writers. He is at the top of his game with Zero Day. Riveting, fast paced, with enough twists and turns to keep you guessing to the very end. This is one hot thriller and hopefully we'll see more of John Puller in the future. I could not put Zero Day down from the moment I read the free sample and finished the 434 pages within 24 hours - about eight hours reading time. This is one great winter read!