d20 Future includes a range of futuristic campaign options for adventuring in sci-fi settings. There are a lot of different ideas for campaigns, including Bug Hunting, Post-apocalyptic, mecha wars, and a return to Star*Drive. Fortunately the campaign settings are only introduced for gamemasters to elaborate on.
A number of prestige classes, building on the d20 modern characters, are included. There are even campaign-specific prestige classes (such as Nuclear Nomad or Bughunter). Of course, there is also gear, and chapters on a number of different futuristic technologies.
The use of a tech level for sci-fi settings helps establish what kinds of gear and tech is available, ranging from near-future to near-godlike. The tech level includes low-tech levels as well, so a gamemaster can easily set the tech level of various planets that starships might visit. In most of the chapters, the technology is kept "real", but a few references to fantastic science are included.
The chapters on different teechnologies really make up the bulk of the book, and provide the most game material. The chapters cover Engineering (including genetic and nanotech), traveler science (space and dimensional travel), starships, vehicles, mecha, robotics, cybernetics, and mutations. A final chapter covers aliens, including some old character races from Star Frontiers.
The starships section was a little confusing in parts, requiring a few rereads. The standard d20 size ratings are not altered for starships, meaning most ships fall into the Colossal range. On the good side, Ship combat is wisely adapted from the standard personal combat rules. I'm not sure whether these rules are compatible with the Star Wars starship rules, but if not, a conversion guide might be nice.
The mecha in the book are more bipedal tanks (similar to Battletech) than anime-style mecha. While this isn't a bad thing, I would have liked to see some reference to more fantastic mecha (even if it was a refence to the d20 mecha book from Guardians of Order).
The mutations chapter covers a range of mutations in classic Gamma World style. Mutations are given a point value, and characters who start out as mutants must balance positive and negative mutations. Unfortunately, its not clear whether a mutated human counts as human for the purposes of bonus feat and skill points. Furthermore, it would be nice to see some sort of scale to let players start out with a slightly more powerful mutant character, setting 10(?) mutation points equal to +1 Level Adjustment, for instance.
One glaring missing chapter was a section on cyberspace and netrunning. Hopefully WotC will address this omission in a future supplement.
A final missing section would be experience adjustments based upon what the characters are facing. How much experience does a character get when facing a 5th level mecha pilot in a Tech level 8 gargantuan mech? It obviously should be more than facing the same mech pilot outside of his mech, and an adjustment based upon different tech levels should also apply - tech level 6 characters should get more XP than a tech level 8 character for facing the same opponent.
Aside from these lacks, the d20 future book is a good resource for gamemasters and players alike.