The GNOME Whitepapers will give you overviews of specific technologies available in GNOME. These whitepapers can be read online as html documents or can be downloaded as PostScript documents for printing.
- GTK+/Gnome Application Development, by Havoc Pennington
- GNOME application programming manual, available in book form and online.
- Writing GNOME Applications, by John R. Sheets
- How to develop applications with GNOME 1.2; covers the canvas and GdkPixbuf. Currently only chapters 2, 3, 10, and 11 are released under the GFDL.