I had a couple of these books and loved them, the ones I had were "Fixed by Camel " and " Who Stole Alligator's Shoes?".
You can see almost all of the series for sale in this listing:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...7969198270&rd=1

I remember these books! I didn't own any, in fact I didn't own many books at all, but I remember checking them out at the school library when I was very young. That auction rocks, btw! Wow, I love collections of books. :D

I am trying to acquire all of the Serendipity books as well as the Sesame Street Library. :D