Designed as a DM's Guide to a science-fiction setting for D&D4e, especially for those intending to run the upcoming 'adventure path' campaign (which rather confusingly appears to be known both as 'Myths of the Far Future' and 'Santiago'), this opens with a bit of atmospheric fiction - at least I think it is, trouble is small black text on a stridently striped background is very hard to read and I gave up and moved on to the meat of the product.
The first section is a campaign overview, and is very much DM only, with such insights to the overall campaign as key players and synopses of each of the adventures that compose the campaign arc. It gives a clear idea of the campaign as an entirety, and includes trouble-shooting hints for dealing with characters who persist, for example, in being on the wrong planet, as well as ideas for mixing in your own plotlines and other modifications. Perhaps you do not like giving characters the freedom of a ship of their own, and prefer them to rent or book passage when travel is required. There is a sidebar (again on that annoying striped background) about using D&D 4e as a science fiction ruleset including how to modify the terminology of the ruleset to suit a futuristic rather than a fantasy setting.
Section two is a gazetteer of planets, giving comprehensive yet compact details about many worlds. Although the DM ought to have the Myths of the Far Future Player's Guide as well, the notes here give additional information on the planets described therein, often things not readily discernable on a casual visit or from reading the databases. It's a useful and fascinating resource, both for running the campaign and for those who want to run their own adventures in this setting.
Next, section three looks at campaigns in space, beginning with thoughts on travel and a glorious-looking (but too small and unclear for actual use - it would make a lovely poster!) starmap. Resources are provided for those who like to create their own planets to add to the worlds of the previous section, as well as notes on dealing with aliens, currencies and adventures.
On to section four, which contains new game rules honed specifically for a science fiction game with this ruleset. These cover new features for characters, firearms and spaceships. It's to be noted that the intention here is to concentrate on adventures taking place on different worlds in the setting, the actual travel is just something you do to get there.
Finally, the fifth section provides enemies. Lots of them. Most walk on two legs, being anything from bandits to native dwellers on particular worlds to law enforcement officers. Some can be used as player characters and there are notes on playing them to good effect. There are one or two beasties, but if it's beasties you are after, hit the Monster Manuals and other bestiaries!
Overall this is a good introduction to science fiction gaming with the D&D 4e ruleset, and this campaign in particular.