They do their work quietly, day in and day out. They punch no time cards, take no vacations, enjoy no pension plans. They're on call 24/7. And, chances are, you gave one of them a homemade birthday card when you were about four years old.

I'm speaking, of course, about our mothers, those wonderful, irreplaceable human beings we honor on the second Sunday of every May.

Mothers may not cut the dashing profile of a firefighter or a police officer. They seldom take a leading role in a Hollywood blockbuster. But what a difference they make in our lives.

Just ask Dr. Ben Carson. In an article for Reader's Digest, this skilled physician praises his mother, Sonya Carson, for making sure that he and his brother, Curtis, made something out of their lives.

In 1961, he writes, the three of them were living in a "dingy multi-family house" in the Delray section of Detroit, "one of those neighborhoods that might politely be called gritty." One day, his mother, who worked three different jobs as a "domestic," came home and turned off the TV set her sons were planted in front of every day and made an announcement: Both of them had to read two books a week from then on and write her a report on what they had read.

She had only a third-grade education, Carson says, "but she was much brighter and smarter than we boys knew at the time. She had noticed something in the suburban houses she cleaned-books." And so she ignored their complaints about how unfair it was and made sure they visited the library on a regular basis. It wasn't long, he says, before he and his brother were devouring every book they could find.

"Only years later would we realize our mother was illiterate and could not read those short book reports we scrawled for her each week," he says. Her persistence paid off: Curtis went on to became an engineer, and Ben is now chief of pediatric neurosurgery at Johns Hopkins Children's Center in Baltimore. Dr. Carson also runs the Carson Scholarship program, which helps poor kids with exceptional academic abilities attend colleges they otherwise couldn't afford.

Think about it. How many children are better off today-physically, academically, spiritually, emotionally-because their mothers insisted that they do their best? And how many other mothers, across the country and across the world, make the same kind of sacrifices for their children every day, without giving it a second thought? The numbers are enormous-and so, too, are the benefits we all enjoy.

That's the message that one group, American Mothers Inc., has promoted since its founding in 1933. Every year, they select a "Mother of the Year" from a field of winners from every state, and this year's winner, Rosalie Gaziano of West Virginia, boasts a "resume" Sonya Carson would appreciate: Four of her sons are doctors (including a Rhodes scholar, two Truman scholars and a professor of medicine at Harvard Medical School) and one is an attorney (Todd Gaziano, who, I must mention in the interest of full disclosure, is a colleague of mine. He directs the Center for Legal and Judicial Studies here at The Heritage Foundation).

American Mothers honored Rosalie for, among other things, her volunteer work in the local community, which includes supporting the University of Charleston and the College of Arts and Sciences at West Virginia University, founding an annual symphony festival in Charleston, and a variety of church activities. She also writes a food-and-travel column for the Charleston Gazette and has published a cookbook, "Seasons & Celebrations" and a travelogue, "It's Your Turn, Chickadees" (which one reviewer on Amazon.com says "offers answers for creatively managing the strain of young family life").

So let's pay tribute to Sonya Carson, Rosalie Gaziano and all the other mothers who deserve our affection-on Mother's Day and every day. Without their love and devotion, the world would be a darker place and many of America's greatest success stories never would have been written.

Those of you whose mothers are still alive should give special thanks this Mother's Day. And those of you who may have missed the opportunity, at the very least remember your mom in your prayers. Without her, you wouldn't be here.

Edwin Feulner is the president of The Heritage Foundation (www.heritage.org), a Washington-based public policy research institute.