Sure libraries are almost irrelevant but this place is a Phoenix jewel for sure. The buildings outside is pretty nice, but inside it's a masterpiece. I'll spare you the descriptions of the glass elevators and the pools of water underneath ... but it's awesome, trust me.
Outside of that ... the entire Phoenix Public Library system is first rate. My favorite parts: they will ship the book you want to the nearest library to you, you can return the book to any location and they allow you to renew your books on-line (they give you an email when it's due and you just click through to re-up, so basically you can keep it as long as no one else wants the book).
First rate and awesome!