American Libraries, the magazine for the American Library Association, is celebrating 100 years and produced a 3-minute video reflecting its history.
[try as I might, I can not get the code to embed correctly on my html page so go here to see the video]
There is a pdf time line available as well. And their A CentenniAL Blog covers interesting things about library hisitory.
Although I have spent all of my professional library career in the school setting, I was a child of the public library and many of the things portrayed here are nice reminders (and funny reminders as well) of many happy hours on both sides of the check out desk in the public and school libraries of my life!