Action moves along nicely, - Lots of science but doesn't sidetrack too much to explain and doesn't use alot of jargon without simple explanations - Lots of outstanding unanswered questions that have to be pieced together so you don't guess the answer too quickly. - Death but not too grisly except for 1 scene early on.
All things I like in a book and get from Mr Crichton's every time.