Tome of Passage

Wondrous item, very rare

Inside this book are pages filled with strange musings and detailed illustrations of impossible staircases and doorways. While this book is set in a bookcase against a wall, you can use an action to tip it toward you and speak its command word. When you do, the bookcase shudders and slides into the wall behind it, revealing a magical passageway. This passageway connects to another wall of your choice within the same structure, provided it's within 300 feet of you and you're familiar with the other wall; the passageway is up to 5 feet wide and 8 feet tall. The passageway magically connects the two walls, creating a structurally sound opening between them that's always 20 feet long (even if it can't be rationalized within the space). You choose whether the passageway's exit is left open or is covered by an unlocked door. The book then topples onto the bookshelf or into your hand (your choice), and this property can't be used again until the next dawn.

The passageway remains for 1 hour. When the passageway disappears, the bookcase slides back out of the wall, and any creatures or objects still inside the passageway are safely ejected to the nearest unoccupied space outside the bookcase.

Table of contents
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Preface: On Metaphorical Spaces

Chapters
1: Basics of Shelving
2: The Importance of Floorplans
3: Scouting, Familiarity, and Everything In-between
4: What Can be Done in an Hour?
5: How a Door Blends In
6: Rooms With No Entrances; an Architect's Primer
7: Advanced Techniques for Infiltration and Misdirection

Appendix: An Architectural Reference Guide of Passageways, Magic and Mundane