There are very few Beverly Cleary books I haven't read - Dear Mr. Henshaw is one of them. I'm not quite sure why it never appealed to me as a kid. It probably has to do with the main character being a boy; I remember reading the Henry books and thinking they were OK but not as good as Ramona.
Dear Mr. Henshaw won the Newbery in 1984 making it next up on my Newbery Project quest (Paul Zelinsky did the illustrations, pretty cool). Leigh Botts is a grade-schooler who moves to a new school when his parents divorce; one of his school projects is to write to an author so Leigh writes a letter to his favorite author, Mr. Henshaw. Mr. Henshaw (occasionally) writes back and Leigh begins a correspondence and keeps a journal addressed to a Pretend Mr. Henshaw. The whole book is told through letters and journals so it reads very quickly, even for a kids' book, due to the amount of white space.
I did like Dear Mr. Henshaw - Leigh is a great character for boys to read. He isn't the cool kid, he's the new one, someone keeps stealing his lunch, and his dad never calls or visits when he promises. He is pretty ingenious, though, and his correspondence with Mr. Henshaw leads him to learn a little bit about himself. But Ramona is still a cooler character (what can I say - I love the cat commercial and dancing in three-way mirrors) and I have no idea why Cleary didn't win the Newbery for Ramona Quimby, Age 8.
Vocabulary (a shorter list and occasionally a time period-dependent list):
kids (i.e. goats)
gondolas (semi-truck related)
reefer (not the pot kind, the trucking kind)