There's a more than a few flaws in his books...
Hi Mark
Not wishing to bash Zubrin's engineering ability, but there's a few gaffes in Zubrin's books, particularly "Entering Space" - which I adore overall, but bits really annoy me. Some specifics:
(1) His anti-Solar Power Satellite argument is a strawman argument of the worst kind.
(2) His Photon rocket using an incandescent tungsten block heated by antimatter annihilation underperforms to a ridiculous degree.
(3) His discussion of the Oort Cloud and low mass objects uses dubious figures.
...but the rest is inspiring.