If you use it like a calculus textbook I can see it working for first contact. But most people won't do that, which makes it not suitable for a "first contact"

If you use it like a calculus textbook I can see it working for first contact. But most people won't do that, which makes it not suitable for a "first contact" introduction. It's superb for people who have some prior experience and can read it in a choose-your-own-adventure way.