I think this is one of the best Crichton's books yet. The plot is very entertaining and original. The action is non-stop, and the writing is good. I couldn't stop reading the book once I started. I am extemely surprised some reviewers found the book slow. Possibly they lack some technical skills necessary to understand what is going on. The book does get a little technical at times, almost a la Heinlein in some his books. But it made only more interesting to me. Anyway, I personally enjoyed the book and would recommend it to anyone.