Distant Worlds is a 64-page softcover campaign setting book for Pathfinder that's like no other: instead of detailing a particular region of Golarion, this book takes you into space! Well-known as one of the few campaign setting-line books to receive a second printing due to its popularity, the goal of Distant Worlds is to provide an introduction and overview to the planets that share a solar system with Golarion. The Inner Sea is great and planar travel has its appeal, but sometimes a story needs to travel to whole new worlds and encounter strange, alien civilizations: if you're inclined in such a direction, this is the book for you.

The front cover is certainly cool and eye-catching, and evokes the "sword and planet" genre that inspires much of what's inside the book. The artwork is reprinted as the inside back cover, while the inside front cover provides a map of the solar system, showing the order of planets from the sun.

The Introduction (two pages) makes clear that this isn't intended as a brand new campaign setting (much less a brand new game like Starfinder), but is instead a whole new set of locales that heroes from Golarion can travel to and adventure on. Thus, the focus is on what outsiders to these planets will experience, and how they'll survive the journey to get there. I especially like the couple of paragraphs on how the gods of Golarion aren't necessarily known deities on other planets, and that their portfolios may be encompassed by deities completely unheard of to the PCs.

The first and by far largest section (48 pages) of this book is a gazetteer of the bodies that make up Golarion's solar system. Each of the planets receives four pages of coverage made up of statistics (diameter, mass, gravity, atmosphere, and orbit), a general description, a few paragraphs on what adventuring there would be like, a half-page chart of key locations on the planet, a couple of pages of written description of those locations, and then a few brief adventure hooks that GMs can use to draw PCs to that planet. Given that entire worlds are being described in just four pages, readers need to have their expectations in the right place: this is an introduction, not an exhaustive treatment. I found the interior artwork very hit or miss: many of the aliens are very cool and evocative, but some of the other drawings are rather mediocre. Anyway, here's a quick run-down of what's covered:

* The Sun: This is actually just a one-page summary, but it's actually kind of cool--I never thought about setting adventures on the sun! In Pathfinder, there's actually stuff there, including magically-protected "bubble cities" that would make an awesome setting for an adventure.

* Aballon: A rocky world that is the closet planet to the sun, occupied by a vast society of machine intelligences created by mysterious (and now departed) First Ones. There's a really cool cultural divide among the intelligent machines between Those Who Wait (who believe that their creators will someday return and justify their existence) and Those Who Become (who believe that they should leave and seed another world, becoming First Ones themselves). Another location that stands out is Horsethroat, a small settlement of about 50 people from Golarion (and other worlds) who have arrived, quite accidentally, through a portal from their homeworld and are now trapped on Aballon. It's a natural starting point for PCs to begin their adventures amongst the stars (even if the "fall through a portal" adventure hook is overused in the book).

* Castrovel: Home to both the elven nation of Sovyrian (with major story ties to the fate of elves on Golarion) and the lashunta, a humanoid race with major and fixed divisions between the societal roles of the sexes. There's a plethora of awesome stuff on these four pages, including some fascinating hints about a mysterious portal network on the planet, some links of which have become dangerous. The ties between Castrovel and Golarion are so strong, it would be fantastic to see an AP that crosses between the two planets.

* Golarion's Moon: This section is only two pages long, but there are some interesting story elements here, as the moon was once colonized by ancient Azlanti, and there's a demon-infested area called the Moonscar (the subject of a Pathfinder module).

* Akiton: That massive four-armed creature on the book's cover is a Shobhad from the harsh, red desert planet of Akiton. This is a classic "sword and planet" setting, but features two races that we'll be seeing a lot more of in Starfinder: the ysoki (ratfolk) and Contemplatives of Ashok (floating giant brains!). I appreciate that the book's author, James Sutter, took care to insert details of continuity from previous Pathfinder sourcebooks, like noting that there's a strong link between the Contemplatives and an artifact found in the Mwangi Expanse on Golarion that was first detailed in Heart of the Jungle.

* Vercies: A tidal locked planet, with a Darkside and a Fullbright area sandwiching a narrow habitable zone along the equator. There's a great picture on page 22 of one of the three castes of the planetwide Vercite species. This is one of the more "high-tech" planets in the solar system and has a nice SF feel that sets it apart from Golarion's traditional fantasy setting.

* The Diaspora: Millions of asteroids, large and small, form the Diaspora. The asteroid belt has a cool history perhaps linked to the Starstone, and is home to a race called the Sarcesians. There's a ton of great adventure possibilities detailed in these four pages, with the Vacant Halls and the Wailing Stone serving as natural destinations for explorers.

* Eox: What if you built the Death Star on a planet, but the one time it was fired it caused untold destruction of your own world? That's sort of the backstory to Eox, a planet where the survivors of a doomsday weapon have turned to necromancy and undeath in order to survive on a blasted world. Eox is one of the most memorable parts of Distant Worlds, as the resident Bone Sages are cool and creepy at the same time. There's a location on the planet called the Halls of the Living which is mad-genius Sutter at his best.

* Triaxus: Interesting concept of a planet with a long (317 years!) orbit, so generations are either "summer-born" or "winter-born." There's a surprising amount of dragon stuff, which isn't really my cup of tea, but it's done well.

* Liavara: An enormous gas giant with several moons. The moons provide lots of variety and adventure possibilities, and I can't argue with the fantastic depiction of a giant creepy bug called The Forever Queen on p. 39 (just pay attention to the little guy at the bottom left to understand the scale!).

* Bretheda: Purple gas giant with natives that are . . . difficult for outsiders to understand. I found the planet's moons to be the most interesting, many of which are so intriguing I wish they would have had additional pages devoted to them.

* Apostae: This is the classic "world-ship" SF trope, and I'm stoked to see it here. My mind instantly jumped to an AP focussed on how to get to the mysterious "vault" at the center of the planet to understand the creators and purpose of Apostae. Interestingly, each resident of Apostae is biologically significantly different to every other one, so the PCs will likely stand out simply due to their (probably) shared humanoid-bipedal features!

* Aucturn: A cool, mysterious planet at the very edge of the solar system. Unlike all of the others, there are no magical portals to Aucturn, meaning it's a hard place to get to! The write-up shows some intriguing links to the Old Ones and the Dominion of the Black, but there's only two-pages of information on this one.

* Other Worlds: The part ends with a two-page overview of some miscellaneous topics: constellations, Cynosure (Golarion's north star), the Dark Tapestry (the haunted void between the stars), and the Ice Belt. I wasn't particularly impressed with the material here, and would rather have seen it used for something else.

Part Two, Stellar Adventures, is just four pages long but they're an extremely important four pages. It's here we get some insight into ways for PCs to travel to other planets, including portals, spells, and vessels. There are brief discussions on how to handle environmental problems (including vacuum, extremely high and low gravity and temperature, etc.). Last, there are two new spells ("Planetary Adaptation" and "Mass Planetary Adaptation") and a new magical item ("Pressure Suit"), all of which are indispensable. GMs planning a space-based campaign should note that this section sets some very broad rules, but leaves the vast majority of questions that are bound to come up to GM discretion. Again, this is an introductory sketch to an interplanetary campaign, not a full rules system.

Part Three, Aliens, is eight pages long. One of the best parts of this section is a list of the couple of dozen of established Pathfinder "monsters" that are explicitly extraterrestrial in origin or that could logically be found on particular other planets. The list is drawn from Bestiary 1, 2, and 3, so there are probably more recent monsters from volumes 4, 5, and 6 that could be used as well. Last, six new alien creatures are given stat blocks and descriptions: the insectile machine creatures called Aballonians, the dirigible-like Brethedans, the previously-mentioned giant brains called Contemplatives of Ashok, the Dragonkin of Triaxus, giant interplanetary "space whales" (capable of being used as transports) called Oma, and the four-armed giants from Akiton called Shobhad. Interesting, creative ideas executed well.

Distant Worlds is a campaign setting book that will either sit on a shelf gathering dust (if you play purely pre-published materials like APs, PFS scenarios, and modules) or serve as *the* book for a homebrew campaign in which the PCs find themselves on alien worlds. It's thus not a must have for most GMs, but if you have serious plans to integrate Golarion's solar system into your campaign, then it's indispensable. There are a ton of great ideas in the book, and even if it's not quite as spectacular as some of the buzz indicates, it represents a worthy expansion of Pathfinder's core campaign setting.