What is personal injury law? 

It is the body of law within tort law that seeks to have a civil system to "make whole" injured persons through monetary compensation. It also functions as one of society's checks on the profit motive of the free market system.

How does it function as a check on profit motive?

The goal of free market profit motive is to maximize profits. Sometimes this is wrongly done at the expense of safety concerns - whether inferior design, inadequate testing, substandard materials, etc. When a product/service does harm to the consumer, tort law allows society to make the victim whole by taking assets from the party at fault. And beyond making the victim whole, the tort system allows society to penalize a party at fault for disregarding public safety. So a person engaging in trade must consider the consequences of actions as part of the business plan. That is a good thing because we introduce and reinforce accountability in the market with the more-efficient judicial system rather than the mind-boggling bureaucracy of the legislative system.

This area of law seems to be a bit suspect at times, is it a scam?

It can be a scam, but to the legitimately injured victim it is often salvation. The difference is whether the victim sees the process as restitution or a lottery win. That perspective is often predetermined before the victim sees a lawyer - not established by the lawyer.

Do personal injury lawyers go through the same education as other lawyers?

During law school the required curriculum is the same for every attorney, and electives may focus toward tort law. After being admitted to the bar, most attorneys fulfill their continuing education requirements with courses focused on their specialty. A lot of personal injury expertise also comes from "apprenticeship" in a personal injury law firm.

Why do people choose this field of law?

Some for profit, some for nobility, some to continue family tradition, some because they are not qualified for other fields of law ... I doubt there is any uniquely discernible factor.

Since everyone likes a good lawyer joke, I had to ask him what his favorite joke was.

A golfer hooked his tee shot over a hill and onto the next fairway. Walking toward his ball, he saw a man lying on the ground, groaning with pain.

"I'm an attorney," the wincing man said, "and this is going to cost you $5000." "I'm sorry, I'm really sorry," the concerned golfer replied. "But I did yell 'fore'." "I'll take it," the attorney said.

It’s no laughing matter when someone gets hurt. Based on what my friend had to say it seems that personal injury law is a legitimate area of practice for good attorneys. Maybe the good ones can start running respectable commercials.