Who is Zinsser's Students from On Writing Well and what is their importance?

Zinsser takes delight in his students at the New School in Manhattan. They in turn cause him to wonder what is wrong with traditional education that makes it turns out poor writers. Meanwhile, his work with the students brings insights into the book that would not otherwise exist. The entire book seems to have been written for his students, and Zinsser invites the reader to this special class that covers more ground than could ever be covered over a single college semester.