Mars is the fourth planet from the Sun and the seventh largest:

orbit: 227,940,000 km (1.52 AU) from Sun
diameter: 6,794 km
mass: 6.4219e23 kg


Hardcopy

The Case for Mars
by Robert Zubrin. A realistic proposal for sending men to Mars cheaply. The ideas in this book are being taken seriously by NASA. There is hope!

Encyclopedia of the Solar System
A more scholarly introduction the planetary science for those who want to dig a little deeper.

A Travelers Guide to Mars
Accessible, heavily illustrated, presenting much of the astonishing information recently learned about Mars, written in a engaging, lively style.

Mars Underground
Fiction by a scientist who knows both how to tell a good story and the territory it is set in.

Mars (Greek: Ares) is the god of War. The planet probably got this name due to its red color; Mars is sometimes referred to as the Red Planet. (An interesting side note: the Roman god Mars was a god of agriculture before becoming associated with the Greek Ares; those in favor of colonizing and terraforming Mars may prefer this symbolism.) The name of the month March derives from Mars.

Mars has been known since prehistoric times. Of course, it has been extensively studied with ground-based observatories. But even very large telescopes find Mars a difficult target, it's just too small. It is still a favorite of science fiction writers as the most favorable place in the Solar System (other than Earth!) for human habitation. But the famous "canals" "seen" by Lowell and others were, unfortunately, just as imaginary as Barsoomian princesses.
Mars



Mars-Opportunity-crater