||Something with the title Isle of the Unknown conjures up an island far from the outposts of civilization, shrouded in mystery, brimming with strangeness and wonders. In this case, only the first aspect is untrue since the island in question is 35,00 square miles in size, broken up into 330 land hexes (each 86 square miles), and each hex is keyed with a central point of interest which includes a number of towns and one city (ruled by a king). But there is mystery, strangeness and wonder aplenty on it.
The island in question is 35,00 square miles in size, broken up into 330 land hexes (each 86 square miles), and is described in much the same way that the Carcosa sandbox setting was -- each hex is keyed with a central point of interest.
Comparisons to Carcosa are unavoidable because Isle of the Unknown is written by the same author, published by same publisher, and is presented in roughly the same format (which is not a bad one) as Carcosa, though it does lack the extensive hyperlinking. So let's take a look at what some of those similarities are.
Like Carcosa, the hexmap is numbered -- each numbered hex corresponds to a location or entity of interest. Like Carcosa, Isle of the Unknown is not a sourcebook that deals in minutae, but provides sufficient information for a GM to flesh out (or even run a fast-and-loose game, since Hit Dice, hit points, and other key information are provided without resorting to stat blocks).
Unlike Carcosa, however, Isle of the Unknown is less concerned with emphasizing the non-standard nature of the setting. On the contrary, Isle of the Unknown takes great pains to allow easy slotting of the setting into an existing campaign -- the culture and political structures of the cities and towns and churches are tackled with the lightest of broad strokes.
Instead the book focuses on three primary types of encounters / hexes of interest scattered throughout the island: magic-users, statues, and creatures.
* The magic-users are clearly non-standard ones: they tend to wear armor not normally associated with their kind, have special innate abilities above and beyond normal mages, and tend to enjoy painted full-page, full-color depictions (which are quite evocative).
* The statues are strange, powerful, and attired in clothes and armor evocative of a fallen Roman Empire (though clearly, one can insert the attire of another great fallen empire appropriate to one's campaign) and can grant abilities, aid or curse visitors, or attack them outright.
* The creatures are primarily chimerical creatures, ranging from larger versions of normal animals (a 6' tall roadrunner), twisted versions of normal creatures (an 8' tall humanoid swan with sleeping human faces on its torso), and -- of course -- mix-and-match combinations of creatures.
Taken individually, these encounters can be used as a magical rogues gallery, a statue encounter list, and a large monster's manual. Together, it suggests something else: perhaps the last flowering remnants of a vastly powerful empire, or a land touched by forgotten gods. The magic-users as described and depicted evoke the feeling of Greek or Roman gods, playfully skirting direct analogues and clearly being less powered; the statues smack of powerfully wrought enchantments that once served some greater purpose, and the creatures seem like echoes of an age when rampant magical experimentation on creatures was the norm.
There are, of course, other types of encounters, but the preponderance of these three suggest that a campaign geared towards exploring the unknown nature of the island would do well to focus on these elements.
Isle of the Unknown wraps all this up with the keyed map, printable Player and GM maps, and appendices that list the locations of all magic-users, all statues, and even provide a visual listing of all the creatures grouped by HD rating.
All in all, a rich setting with a lot of usable material the could have perhaps benefited from a few more hints on the origins and nature of the mysteries of the island -- without necessarily setting it in stone, of course.
[5 of 5 Stars!]