Helen - could the book you're talking about be "Carry It On, the Story of America's Working People in Song and Picture," by Pete Seeger and Bob Reiser? This is a good-sized paperback, some 250 pages of songs with a bit of commentary mixed in. This one is still available from Sing Out! You might want to take a look at their web site sometime - they have a number of publications available.
-Joe Offer-