This book has a new mechanic of sorts called tricks. You can have 1/2 your character level in total tricks, and each one costs 2 skill points to learn and can be used once per encounter. For example, one trick is acrobatic backstab, you need 12 ranks in tumble to get it (which costs 2 more skill points to buy the trick). Then, once per encounter, you could tumble through someone's space (IIRC, that is a DC 25 tumble check, +2 per extra person threatening you). If it works, then they are flat-footed against your next melee attack (meaningyou could sneak attack them).
There are also these new kind of feats with a [Luck] descriptor. They each grant an extra 'luck reroll' per day, one of them actually gives you 2 extra luck rerolls, and something you can use your 'luck rerolls' on. So one feat might let you spend a luck reroll to reroll certain kinds of skill checks, or reroll a saving throw, and then you spend your luck uses on those abilities however you like. There is one that lets you turn a natural 1 on a saving throw (auto-fail) into a natural 20 (auto-succeed), but you can only use that one once per day, even if you have more luck uses than that. There's a similar one for an attack roll too.
There are some multiclassing feats that are pretty good, ie lets you multiclass monk and ninja, and you add those class levels together to determine your ninja ki pool and monk unarmed damage. The prestige classes are okay, I think the most interesting one is Combat Trapsmith, it lets you make and set traps during combat. Main problem with it is I don't think the traps are powerful enough, even the best ones only do like 5d6 damage (reflex half) or duplicate a 2nd level spell.
There isn't many new magic items, but there are new alchemical items and poisons. There are also a few 'living items', ie a bottle with a super-brite firefly that you can use as a torch (but you have to keep him fed and such).
There is also a bunch of advice stuff, like how to run a 'scoundrel' game and how to make scoundrel characters, etc. The making scoundrel advice isn't too bad really.
