Books such as the Dungeoneer's Handbook by Paizo need to be really good to impress me. At US$10.99 for a 32 page book, you're paying a premium price for not very much information, and so the book has to be superb to be worth the cover price. The book looks beautiful, with full colour throughout and glossy pages. It's a Paizo book, and they have great production values. But what does the book include?
The book starts with an overview of dungeons, dividing them into categories (Conquered, Fortress, Guardian, Natural, Overrun, Ruined, Magical and Mega). Following that is a discussion of Preparing for a Dungeon, and then one on Traps. The section on Monsters discusses how players can do more with monsters than just kill them, and then a section on Treasures concentrates on how to carry treasure as well as alerting the reader that knowledge is as much a treasure as gold or magic.
Two pages are devoted to a major new concept: Dungeon Guides, books that have been written by past explorers that give help to adventurers exploring the dungeon they describe. In particular, they give bonuses to certain skill checks in a dungeon, as well as having an intrinsic accuracy rating that allows knowledge-like checks for such information as what lies ahead on the map, hints on how to solve puzzles, or the location of traps.
A section on Famous Dungeons of Golarion, which mostly matches a map on the inside cover, gives brief descriptions of some of the dungeons that have appeared in Pathfinder products, although it doesn't give where they appeared, which irritated me. A section on hirelings gives very brief description of Chroniclers, Fences and Sages before spending most of the time describing the Torchbearer.
New Archetypes are given for Rangers (Dungeon Rover), Monks (Terra-Cotta Monk) and Alchemists (Trap Breaker), and there are six pages of new equipment and two pages of new spells. Finally, the back cover gives four new regional traits for those born in or around dungeon locations.
The first half of the book mostly consists of advice on dungeon adventuring, but its nature makes me query what audience this book is for. Some of it, such as the types of dungeons section, would far better be in a DM supplement than a player supplement. If the book were aimed at beginners, I would have liked to see discussion on mapping techniques, party marching order, listening at doors and similar basic techniques needed to survive a dungeon along with the other advice. However, that isn't included. Instead, there's advice on talking to monsters and researching dungeons before you enter them. This isn't to say that the advice is poor: what is included should help a group prepare for the challenges a lot better. However, there's a lot of words to say not all that much, and much of it which most players probably knew. (Did you know that a bag of holding helps you carry treasure?)
The game material suffers from a common problem with Pathfinder supplemental material: it's too specific in effect. Characters don't get enough feats to be wasting them on stuff like Arcane Trap Suppressor (your dispel magic or greater dispel magic lasts 1d4 minutes against magic traps instead of 1d4 rounds) or Cursed Item Detection (+2 bonus to identify magic items, and only need to beat the DC of an object by 5 rather than 10 to determine if it's cursed). That last might be useful if your GM hates you and keeps putting in cursed magic items, but how often will it really be useful in a game? Let's point out that the feat doesn't scale like Skill Focus or Magical Aptitude (which double their bonus once you have 10 ranks in a skill), and the comparison becomes particularly painful.
Some of the items are quite nice: the thieves' ring, which conceals a set of picks is great, as is the phosphorescent gel, which glows for an hour before exploding in a burst of light and flame. However, I'm particularly unhappy with the Thieves' Tool Extenders, which allow you to unpick locks from five feet away (or longer). As a non-magical device, they seem quite impractical.
Six spells are presented here, few of any general use. Create Holds, which creates hand-holds to climb a wooden or stone wall, but not metal or anything harder, is actually less useful and of higher level (for druids) than Stone Shape. Determine Depth (which determines how much barrier there is between you and open space) is particularly amusing for the DM as there's a maximum depth it can determine and all distances above that are reported as that depth. So, does the DM actually mean 50' or 500'? Let's teleport and find out! (Or not).
However, the winner of most bizarre spell of the book goes to Nature's Ravages, a spell which ages a corpse (1 day/2 caster levels) so that it decomposes more rapidly. Unfortunately, there's no indication of what this does to an average corpse. How long does it take a human corpse to become purely bone? Or dust? The kicker is that there's actually a Greater Nature's Ravages spell as well – Cleric 8, Witch 7 – which ages a corpse 1 year per caster level. It's a nice idea, but its usefulness is extremely debatable.
The AD&D Dungeon Master's Guide had an extensive section on hiring sages, giving details as to their knowledge of various areas and how long it would take to find the answer. That was before the Knowledge skills were introduced in 3E, so the Pathfinder version doesn't need to be as long. So how good are a sage's knowledge skills? No idea. It costs 15 gp per day to hire a sage, and "given time, a sage can puzzle out the answer to almost any question or riddle relating to her area of expertise." Actual bonuses for Knowledge skills? None are given. Useful, this is not.
Far more attention is given to the torchbearer. At 5th level, a character can take the Torchbearer feat, which allows them to take a 1st-level cohort (alchemist, bard, fighter, ranger or rogue only) into the dungeon who must take the Torch Handling feat (allowing them to use the torch as a simple weapon, increase the light radius of the torch, and to reroll one saving throw that might extinguish the torch). At 8th level, the Torchbearer feat changes into regular Leadership, and your torchbearer now follows the normal rules for cohorts. Oh, and three torchbearer archetypes are also given, which can be taken by regular PCs… if you want bonuses to hide with your horses, this is the way to do it! It should be noted that none of the torchbearer's abilities allow them to survive better in the dungeon, so let's hope a troll doesn't attack them or they get in the area of effect of a fireball spell. Wouldn't it be easier to just hire a local lad to hold a torch in the dungeon for a few gold a day?
Ultimately, I can't recommend the book at all. Trying to find things I like in the book is exceedingly difficult, and I can't really see my players using much of it. It reads like a book written its four authors to fill a slot in the monthly publishing schedule, which it probably was.