Mars tells the tale of the first landing on Mars and the political deals that go on back on Earth. Two groups of people fly the 100'000'000 kilometers to Mars and gently fall to the ground. The tale than moves to the epic tale of exploring a whole planet and the lifes of the people who made it there.
If, like me, you're one of those people who can't wait to ride on the next interplanetery ride to Mars then you'll love this story like I did. Scientifically speaking, theres a lot happening to, though if you don't like geology theres probably not a lot there for you - although there are surprises on the way.
It all leads up to a fight for survival and rescue mission but on the way you visit all the best sights of Mars.
Return to Mars is a follow up story to Mars but is grounded much more in current, real technologies that could take us to Mars for real. To me this made it feel too clinical with less fantasy, it lost some of the magic of the first book.
Also, the story was not as engaging as the first, and leans more towards petty differences between the characters. It also relies much more on the on going Grand Tour, Ben Bova develops through-out is books and does not work as well as a single story.