Here are the few links where you can get some technical books......
GIMP
GIMP Tutorial Index
A Tutorial for Perl GIMP Users
A Scheme Tutorial for GIMP Users
GIMP Guide
The GIMP User Manual
Pseudo 3-D with GIMP
Graphical Photocomposition with GIMP
Creating Text with the GIMP
Creating Fire Effects with the GIMP
Creating and Editing Animations with GIMP
GIMP-Perl: GIMP Scripting for the Rest of Us
Writing a GIMP Plugin
GIMP: The RRU Tutorial
GIMP User FAQ
Script-Fu Tutorial
The Quick Start Guide to the GIMP, Part 1
The Quick Start Guide to the GIMP, Part 2
The Quick Start Guide to the GIMP, Part 3
The Quick Start Guide to the GIMP, Part 4
GNOME
Application Programming Using the GNOME Libraries
Part 1: Everything You Need to Get Started
Part 2: Building a Sample Genealogy Program
Part 3: Adding File Saving and Loading Using libxml
Creating GTK+ Widgets with GOB: An Easier Way to Derive New GTK+ Widgets
Handling Multipel Documents: Using the GnomeMDI Framework
Livening Things Up: Graphics Made Easy Using the GNOME Canvas
Developing Gnome Applications with Python - Part 1
GTK
GDK Reference Manual
GLib Reference Manual
GTK+ Reference Manual
The GIMP Toolkit
GTK+ FAQ
GTK V1.2 Tutorial
Drawing and Event Handling in GTK
An Introduction to the GIMP Tool Kit
Gnuplot
Constrained Dynamics
Continuum Dynamics
Differential Equation Basics
Energy Functions and Stiffness
Particle System Dynamics
An Introduction to Physically Based Modeling
Rigid Body Dynamics I
Rigid Body Dynamics II
Scientific Visualization Tutorials
Gnuplot - An Interactive Plotting Program
GIF Animation Tutorial
HTML
HTML Table Tutorial
HTML by Example
How to Use HTML 3.2
Creating a Client-Side Image Map
Advanced HTML: How to Create Complex Multimedia Documents for the Web
The ABCs of HTML
Sharky's Netscape Frames Tutorial
ILU
ILU Reference Manual
Using ILU with ANSI C: A Tutorial
Using ILU with Java: A Tutorial
Using ILU with Python: A Tutorial
IP-Masquerading
ipchains: Packet Filtering for Linux 2.2
Setting Up IP Masquerade
Setting Up IP-Masquerading
Ipchains: Easy Links to the Net
Linux Networking Using Ipchains
IPC
Advanced 4.4BSD Interpprocess Communication Tutorial
UNIX Multi-Process Programming and IPC