鋼の錬金術師 パーフェクトガイドブック [Hagane no Renkinjutsushi Perfect Guide Book]

This is a companion guide series from Square Enix, running from 2003, that collects reference material for Hiromu Arakawa's Fullmetal Alchemist manga. The books compile character profiles, world-building notes, and behind-the-scenes commentary, offering fans a deeper look at the alchemical world of Amestris. As an official resource, it serves as a key companion to the original series, though it contains no original comic story content.