Adobe Font Development Kit for OpenType (AFDKO) Overview
OpenType Feature File Specification

MakeOTF v2.5 User Guide
Command Line How-To
CID-keyed UFO Guide

Issues with OpenType/CFF and TrueType fonts in MS Font Validator
Practical issues in weight setting and style linking (Windows only)
A few notes on otfautohint

FDK Build Notes
MakeOTFEXE Feature File Parser Notes