Gentoo developer manual is a document that contains all sorts of information, best practices, references, etc. related to working on Gentoo. Writing ebuilds, writing eclasses, maintaining keywords, you name it - it is all covered by the dev manual.
This wonderful document was written by Ciaran McCreesh, with some (very minor compared to main body) contributions from other developers.
Copyleft © 2000-2006. You are allowed to reproduce these pages intact, as long as you clearly indicate the source of information (this URL). You are allowed to redistribute modified copies of these pages, as long as you clearly indicate the source (this URL) and that you made modifications. You get the idea, right?