Well, kindergarten USED to just be a gentle introduction to school, where children mostly learned through play, and learned how to socialize with other children and be away from their parents. At least, that's how it was in the 1960s when my parents were young children. Preschool didn't even exist back then, because kindergarten essentially was what preschool is now. Over the years, they've started making the curriculum more difficult and placing more demands on the children. Kids are basically learning things a year earlier than they used to...kindergarten is now more like first grade, and in first grade they're pretty much doing what used to be second grade curriculum, etc. So, if you do want your child to have a year where they are gently introduced to a classroom setting before just throwing them into their first "real" year of school, you definitely should send them to preschool.