When was the first time you really got to know someone whose culture and background were different from yours?  For many, such an acquaintance occurred first in school.  Prejudices have abounded here as well, of course, but there have also been opportunities for overcoming them.  Whatever the experience, Waltham's public schools, like Waltham itself, has long nurtured a diverse population and has been both challenged and rewarded by the demands of the multi-cultural experience.   With conscientious teaching Waltham's students learn, while noting differences, to focus on what we all have in common, to consider themselves as part of a global society, and, ultimately, to make decisions and find solutions that benefit the greatest number of people.