You can't beat the page count or the depth of detail. This is not an expansion for the faint of heart; but for those willing to put in the time, it will produce a gaming experience that is unmatched.

If you're looking to add a little extra verisimilitude (and tons of gory details) to your roleplaying combat then Trauma's definitely the book for you. It's written with the developer's own "Fantasy Dice" system in mind, but can be adapted to any other system with relative ease (and there are notes on the Radical Approach website for conversion to some common systems, including D20, GURPs, and World of Darkness).

There's a huge amount of information crammed into the book's 189 pages, so it's easy to get overwhelmed if you're not careful. I recommend picking and choosing only the parts you want to include in your game rather than trying to adopt absolutely everything (unless you're of a particularly simulationist bent). Surviving a brutal fight with a dozen orcs only to die of gangrene a couple days later might be medically accurate, but is probably going to be unsatisfying for your players (again, unless they signed up for a really hardcore simulation). Still, used with moderation, it's an excellent resource not just as a wound system but also to give you ideas for descriptions during and after combat. There is also enough colourful flavour text to avoid it becoming an overly dry medical textbook. I would definitely recommend picking it up!

This book is quite possibly my favourite purchase from this website. The book opens up with the usual "why this book was written and how it should be used" blurb; in this case, as inspiration to writers, to provide healers with something more interesting to do than either roll a healing check or cast a healing spell and move on, and to provide warriors with more varied and interesting descriptions of what their attacks have done. Also, he didn't like the idea of someone's cause of death simply being "lack of hit points".

Next comes the bit about finding out what's wrong and how to fix it; it's all fairly detailed, with medieval and modern methods described in detail followed by ideas for futuristic methods and a collection of healing spells for a fantasy setting; from eliminating infection to regrowing bones and tissue.

Then comes the meat of the book; chapter after chapter of detailed information about the various parts of the body and the various hideous things that can happen to them in combat, as well as rules for bleeding, infection, shock, burns, broken bones, hypo- and hyper-thermia, anaemia, spinal injuries, dehydration and stroke. This section makes for interesting reading even if you don't plan on using the rules, as it is (or at least seems - neither I nor the author is a doctor) medically accurate and covers just about anything that could happen to the body once sharp pieces of metal (or fast moving pieces of lead, or fireballs etc.) are introduced.

Finally, there are the Trauma Tables; these rules are designed to be used after the combat is over, so as to avoid slowing down the combat. The wounds range from Superficial to Mortal, going from "That'll probably leave a scar" all the way to "Unable to halt or slow the impact, the skull explodes in a rain of brain and bone fragments. Bleeding (massive); Incredibly dead". Each entry refers back to the more detailed section, which in turn is used for healing (where appropriate) once the combat is over. This section also includes damage tables for electrical burns, which can have other, nastier effects than normal burns.

There is a free PDF available from the publisher's homepage which gives advice on using this book with a few different systems (including d20, World of Darkness and GURPS), and it runs very well with the system for which it was designed. The artwork is pretty cool, and if you have any trouble converting the book to run with your system of choice, the author is usually more than willing to answer questions (such as my ones about using it to emulate energy weapons).

In short, if you've ever wondered how your preferred system would play with the introduction of medically sound damage modelling, this is the book for you.

Essentially Trauma is a medically correct and system-agnostic version of Arms Law's critical hit tables. Each chapter details all the things that can go wrong with a hit location (Head, Chest, Abdomen, Arm, Leg), with tables at the end for random results. Unlike Arms Law, these trauma results apply after combat; during combat, this supplement reasons it's faster and easier to use existing game systems and assume adrenaline hides immediate. It also describes what first-aid and medical techniques of the past, present, and near-future can ameliorate or repair the damage. If you're at all curious about what really happens to the human body when it's stabbed/sliced/bludgeoned/burned, or you think medical accuracy would enhance your game, buy this supplement.