Well, not forever.
But due to Contra Costa County budget cuts, the libraries will be closed from Wednesday through Sunday, and then from Thursday, December 31 (New Year's Eve) through Sunday, January 3.
But you get some leeway for returning books. Due dates for all items will be extended so that no materials will need to be returned Monday, January 4. During the closure, all book drops will be closed.
So, don't worry, you can hang on to that copy of War and Peace and maybe get it finished during the holidays--especially if, like me, or many employees of Walnut Creek, you are on a required break from work between Christmas Day and Monday, January 4, due to forced vacation or furlough.