D&D Guildmaster's Guide - Maps *

Here’s a brief description for the maps accessory you’re referring to:

D&D: Guide to Ravnica Map / Dungeons & Dragons – Guildmasters’ Guide to Ravnica: Maps & Miscellany – Brief Description

An official Dungeons & Dragons maps accessory tied to the Guildmaster’s Guide to Ravnica campaign setting. This pack contains a set of detailed, dry-erase-friendly maps and visual tools designed to help Dungeon Masters run adventures in the city-plane of Ravnica — the sprawling, guild-ruled urban world from Magic: The Gathering. The package typically includes multiple double-sided maps (showing parts of the Tenth District and various iconic locations tied to guild activities) along with reference information and quick-use charts to make encounters, exploration, and planning easier at the table. (nexus.is)

It’s not a storybook or rulebook but a tactical/visual aid you use alongside the Guildmaster’s Guide to Ravnica sourcebook to bring the setting’s locations to life during play. (nexus.is)