This book is superb for a number of reasons. It's chilling in its believability. You really do feel that a park filled with dinosaurs could be like this. It also has a tonne of stuff that didn't make it into the movie. As much as I adore the movie, I think I prefer the book. Its that good.
The science is flawed, of course. But Crichton was getting his readers to think about themes, including the dangers of corporate-driven arrogance mixed with scientific power. SHOULD we bring back dinosaurs if we could? You'll be asking yourself that, even if your answer beforehand was "hell yes!"
The technical detail is really well done, as is the corporate angle (represented by John Hammond, who is much more cynical and arrogant here than he is in the movie).
I love this book. It's brilliant, genuinely scary, fascinating, and exciting.