Take it from someone stationed in Korea. As I read this it took me back to Area 1. If you were ever part of 2ID, reading this is like reading about your day. He mentions places in Korea that anyone in Area 1 has visited. For you civilians out there, Area 1 is the north most area designated by the US Army.
Callahan occasionally makes a few remarks or talks about a few things that dont fit - such as the use of Cell phones on the battle field. Anyone who has been to one of the training areas in Korea knows that the KTEL cell network does not extend up there. He has the insider knowledge, and uses it. Few books will ever refer to the 'kettel' when talking about Soju (for example). Callahan also portrays an important military issue - technology.
Todate the M1A2 Abrams MBT is a very technological beast. While NKFOR do have a modern fighting force, by the third book we are looking at the war after the decimation of the initial attack on South Korea. Seeing the use of very basic and crude military technique is brilliantly done by the author. If one were to take the book apart and look at it one sees that Callahan is invested in the belief that technology can lose a war, and that for the same reasons we faced tragic losses in the 1950's we could still be lose a war in Korea again.
His characters are deeply evolved and through the story line you see them change, adapt and overcome. I could not put this book down. If you love armor, or have ever studied (or been part of) potential modern Korean war issues this is a must read. The story is fast paced. While you dont get the stratigic and theater details of say Tom Clancy, you get the low level unit interaction, and daily life view brilliantly portrayed. His characters lives are run by the conflict and not by some more traditional selective killing off, if your not dis-satisfied by who lives and who dies, you either live in a fantasy world where bullets cant kill, or readin the wrong book. Reading this book, his characters reminded me of people I served with there, and people I serve with today.
His book didnt make me imagine the place, it put me there, and his technical account of things gives even the layman enough information to understand some of the complexities of the modern battlefield. I can not stress how good this book is. I could not put it down, infact, after picking it up at the store at 9pm, I didnt stop until 2am when I finished the book.
In an off note - Borders tends to only stock the third book of the series (this one), so you will probably have to buy the first two books online.