From the back of the book:
Maelstrom Domesday is the new incarnation of Maelstrom, the classic RPG from 1984.
This book brings you various maps, charts and plans to enhance your Maelstrom Domesday game. Regional maps to work out where your place in the kingdom is. Town, manor and village maps to provide a base for your investigators or adventure locations. The building maps are for when things are a bit more personal.
This book is useful for Referees and Players alike, as a reference to the world in which the characters live and as inspiration for planning an adventure.