So I've always found it a bit of a bummer that Doogie Howser, Military Psychic is instead just plain Carl, Military Electronics Nerd in the book. It's an interesting concept portrayed pretty well by Neil Patrick Harris. Honestly, though, the idea was rather wasted by the script: Harris' character pretty much exists to give the iconic "It's Afraid!" line at the end of the movie. Anyway:

Heinlein does a great job hooking the reader's attention in these opening chapters, especially considering that much of it consists of lengthy speeches by various teachers and military men laying out their philosophy. The most famous one even made it (with a few changes) into the movie:

Anyone who clings to the historically untrue — and thoroughly immoral — doctrine that ‘violence never settles anything’ I would advise to conjure up the ghosts of Napoleon Bonaparte and of the Duke of Wellington and let them debate it. The ghost of Hitler could referee, and the jury might well be the Dodo, the Great Auk, and the Passenger Pigeon. Violence, naked force, has settled more issues in history than has any other factor, and the contrary opinion is wishful thinking at its worst. Breeds that forget this basic truth have always paid for it with their lives and freedoms."

There is an interesting contrast and comparison here between Heinlein and Roddenberry('s writers). As much as I love Star Trek, Picard is wrong when he contradicts Colonel DuBois that "power flows from the barrel of a gun." Even Trek seems to concede this with the Hugh debacle: Picard had a chance to destroy the Borg forever, but got cold feet and decided not to go through with it, a mistake that lead to an untold amount of death and suffering at their cybernetic hands throughout the galaxy. Indeed, the writers seemed to concede this point in spectacular fashion with an entire series called Deep Space Nine. Sure, Sisko attempted diplomacy at various points -- but talking is never the answer, not against the implacable Dominion. It took the Federation years of grit, tenacity, blood and sweat to finally throw off their would-be oppressors. DuBois understood this, while Picard railed against it -- and even in Trek's optimistic world, indirectly made the whole galaxy pay for his decision.