The GeoServer website has featured GeoServer Beginner’s Guide by Stefano Iacovella and Brian Youngblood for a couple of years now. In addition to being an excellent resource, a portion of each sale goes back to the Open Source Geospatial Foundation.
The publisher, Packt, has extended a 50% off three-pack deal (to introduce two new GeoServer books):
GeoServer Beginner’s Guide by Stefano Iacovella and Brian Youngblood
GeoServer Cookbook by Stefano Iacovella
Mastering GeoServer by Colin Henderson
To use, add all three books to your basket and enter the discount code “ggm50”. The code can only be applied to the basket once (even if you cancel). If you have any trouble pester @PacktPub on twitter or email. The offer is good until the end of March (for ebooks and pdf).
**Update: **If you had trouble with the instructions above a new code has been provided: “gbgcmg50”