State of Text Rendering. Behdad - A good read to understand the pieces of the Free Software text rendering stack.
Behdad Esfahbod's personal website - Lists many resources related to text rendering
Most of the progress and innovation in Free and Opensource text rendering is entangled with personal story and struggles of some of brilliant engineers. Here is Behdad's story written by himself.
Text layout is a loose hierarchy of segmentation - Raph Levian
Fonts and Layout for Global Scripts by Simon Cozens
Modern text rendering with Linux: Overview, which has a Linux focus and explains Pango in more detail