Martian Walker and Other Stories

This book is a collection of four science fiction stories, each unrelated to the others, but all focusing around the need to rely on one another to beat the odds and win the day. They range from a relatively hard sci-fi look at transhumanism on Mars, to a hapless human tourist caught in an alien civil war, to an alien patrol vessel seeking to save Earth from being wiped out, to a human soldier looking to go behind enemy lines on an alien planet for a very good reason.