Every five years since 2000, we have put together a list of 100 Leading Women in the North American Auto Industry. It's always challenging. Twenty years ago it was hard to find enough executives with authority; this year, the challenge was choosing among hundreds of powerful female executives.

In 2000, when we put together our first list of 100 Leading Women in the North American Auto Industry, we had a difficult time finding women in authority. But times have changed. This year, in assembling our fourth list, we struggled to choose among hundreds of powerful female executives.