The No Child Left Behind Act (NCLB) was passed in 2001 to increase accountability and improve public education outcomes, requiring annual student testing in reading and math with the goal of all students reaching proficiency by 2014. It affects teachers and students in grades K-12 and aims to promote equal education opportunities, but has been controversial with both positive and negative impacts debated. While it increased accountability and parental involvement, critics argue it led schools to focus too narrowly on test preparation and limited curriculum flexibility.