We'll tell you up front we've decided to make social pioneering a special-recognition category, separate from our all-time list of the 33 drivers who make up our Indy 500 Field of the Century.
It would simply be impossible to choose which social pioneers to include, and which to omit.
How could we include Danica Patrick, the first woman to lead the 500 (in 2005), and omit Janet Guthrie, the first woman to attempt to qualify (1976) and to race (1977) at Indy?
And what about Lyn St. James, the Indy rookie of the year in 1992 with an 11th-place finish, who competed in seven 500s -- and who brought Patrick, as a teenager, to the Speedway for the first time, as an intern?
Then there's Sarah Fisher, the youngest woman to compete at Indy, at age 19 in 2000.
And then what about William Theodore Ribbs Jr. -- "Willy T." -- who in 1991 became the first black driver to qualify for the 500?
Include one or more of the social pioneers, and you slight the others by default. Include all five, and pure racing is somewhat displaced by sociology as a criterion.
So here's to the groundbreakers
Indy 500 starts: Four
Best finish (year): Ninth (1978)
Laps led: 0
First woman to race at Indy. Arrived in 1976 to endure a storm of hostility, including some whispered lewd comments from some male drivers, but failed to record an official qualifying attempt.
Started 26th in '77 and raced under terrible hardship. A fuel spill during a pit stop left her soaked in methanol, and after the race there was no shower in Gasoline Alley for women. So some crewmen had to hold up panels in the male showers so she could wash off the skin-blistering fuel. She marched into the media center for an impromptu press conference to protest, drawing mainly snickers from a largely chauvinist media corps.
Quieted the critics somewhat in '78 when she started 14th and finished ninth.
Indy 500 starts: Six
Best finish (year): Third (2009)
Laps led: 19
Has had far and away the most visible impact among women drivers at Indy, and has been easily the most serious female threat to win the race, but had the way opened for her by Guthrie's ordeals of the '70s.
First woman ever to lead the 500, in 2005. Led with seven laps remaining, but had to slow down to conserve fuel and was passed by eventual winner Dan Wheldon.
Almost won the pole in that rookie year of '05, but a slight gust of wind spoiled one of her four laps and she started fourth, where she would finish.
Feisty demeanor and glamorous style have made her the most popular female driver ever at Indy, and the most popular driver in the IndyCar series today.
Has shown only flashes of delivering on the promise she showed in '05. Only IndyCar series win came at Motegi, Japan, in 2008. Third-place finish at Indy in '09 is best ever there by a female driver.
Lyn St. James
Indy 500 starts: Seven
Best finish (year): 11th (1992)
Laps led: 0
First woman to win rookie of the year honors at Indy, with an 11th-place finish in 1992. Seven 500 starts were most by a woman until Sarah Fisher in 2008.
If Guthrie blasted through the barriers for Patrick, it was St. James who literally brought Danica through the threshold. When Patrick was 15 and a go-kart champion, St. James brought her to Indy as a team intern.
Willy T. Ribbs
Indy 500 starts: Two
Best finish (year): 21st (1993)
Laps led: 0
First African-American driver to qualify for Indy 500 in 1991. Had made brief efforts at NASCAR, but best racing year was 1983, in the SCCA Trans-Am series, when he won five races and was Pro Rookie of the Year.
For the '91 Indy effort, Ribbs and car owner Derrick Walker got basic funding from comedian Bill Cosby, and after Ribbs made the race on the last day of qualifying, they hoped outside corporate sponsorship would flow in.
As it turned out, "McDonald's threw a few hamburgers at it," Ribbs recalled recently of the funding offered by the corporate giant at the time.
Ribbs raced in eight other Championship Auto Racing Teams Inc. races that season, with three top-10 finishes for 17th place in season points.
Indy 500 starts: Nine
Best finish (year): 17th (2009)
Laps led: 0
Youngest woman driver to race in the 500 at age 19 in 2000. Became youngest female car owner at Indy when she formed her own team in 2008 at age 27 and qualified for her eighth 500, setting the existing record for starts by a woman.
Ed Hinton is a senior writer for ESPN.com. He can be reached at firstname.lastname@example.org.