Antique/Collectors...have no clue?

I have 3 sets of books...that I know very little about. I would love to find what they are worth.

They were put out by the Grolier Society...I'm guessing one set maybe early 20's... the other maybe early 30's.

I have the entire set of Grolier Encyclopedias. Excellent condition. Whats so neat about this set is there are only 10 books all together forming the entired group. Thats A-Z...with STR-Z making up the last book. We've come along way since then..lol

The front cover reads like this:

COPYRIGHT 1949 BY THE GROLIER SOCIETY INC.

GROLIER ENCYCLOPEDIA
Copyright, 1944,1945,1946,1947,1949 by the Grolier Society Inc.
________________________

DOUBLEDAY'S ENCYCLOPEDIA
Copyright, 1943 by the Grolier Society Inc.

Copyright, 1931, and so on till 1941
by the Doubleday, Doran & Company, Inc.
_______________________


Then there is the Book of Knowledge

10 books to the first color...numbered 1- 10

The earliers copyright on this book is 1922.

Then the books change outsides..and as I look at, I find that its an annual.....and numbered by the year. Starting with 1951 and I have up till 1973.

They belonged to my grandparents...the thing I have always wondered about besides thier worth, is there is a bookcase, that they were in, when they were in my grandparents home, they books, are still in that case...its beautiful oak, and still in excellent condition. I wondered if it were a part of the purchase or not?

Anyone know anything about books? Or where I can go to find out? Or has anyone seen a set like I'm talking about? I'd be interested in knowing...

Thanks......