Having deployed to Iraq, and spent the last 6 years flying Helicopter EMS, I tend to be overly qualified to answer these questions and as a result I find myself retreading the same terretory again and again.
A well equipped trauma/field-surgery/"little black bag" should contain the following...
Mask & Gloves
Bandages/Dressings, in assorted shapes, sizes, and types
Suture Kit, Needles, thread, and snips (all Sterilized)
An assortment of Hemostats, for poking, prodding, and clamping.
Chest and endotracheal(throat) tubes
Sulfa Powder(or equivelent)
Drugs, Most importantly pain-killers and antibiotics
In addition your Doc is going to want cold water, boiling water, clean towels/gauze, and a clean/well lit place to work. Obviously something may, or may not, be available depending on setting but the basics don't change.
For details on specific injuries/treatments checkout;
It was written for grunts like me wich means they use simple words and lots of pictures ;)
Hope this is Helpful.