Before 1918, when Mississippi became the last U.S. state to require that school-age children attend public or private schools, many children were taught by their parents at home or by teachers informally hired by the community. Quite often in rural areas, kids of all ages were taught in the same one-room schoolhouse.
Decades later in the 1980s, homeschooling made a comeback when religiously conservative parents convinced states to approve and give full credit for the teaching of children at home. The homeschooling movement has since broadened to include parents of all faiths - or no faith at all.
In this photo of an old, one-room classroom in Grundy, Iowa, the 7-year-old boy getting help at the blackboard is the only second-grader in the class.
Thus, an estimated 1.5 million American children - about 3 percent of the school-age population - won't be going anywhere as schools open for the fall term.
Instead, one or both of their parents will gather books and other materials, prepare lesson plans, and teach their children everything from algebra to zoology right in their living rooms.
Homeschooling's big selling point for many parents is the argument that children get their ethical values from the people with whom they spend the most time.
Adults who choose to stay home and teach their children often object to standardized testing and what they see as the regimented way in which schools group students by age rather than ability, and pass them ahead to the next grade whether or not they've grasped the material.
The idea that one parent, or even both, make the best teachers, and home makes the best classroom, has long been accepted in many parts of America.
In home-schooling households, it's not unusual to find several children, ages 4 to 16, being taught together. Older kids help younger ones, as they once did in those one-room schoolhouses.
Many home-taught students excel in several subjects and have no trouble moving on to college, often with academic scholarships in hand.
But critics point to home teachers' lack of experience and credentials. No one's supervising them, say. And they argue that pulling kids out of school may deprive them of social skills.
Home-schooling parents dispute the notion that their children are socially isolated and bookish. They are, the parents say, simply hard workers who go to scout and church meetings, play sports, and shop at malls right alongside their friends who go to school.