The Interior Design Handbook: Furnish, Decorate, and Style Your Space
Clarkson Potter · Best for the actual numbers: heights, clearances and rug sizes

Frida Ramstedt's 240-page illustrated handbook is the closest thing this category has to a rulebook - proportions, measurements and placement, drawn as diagrams rather than described in adjectives.
If you buy one book off this page, buy this one. Nearly every decorating mistake I get called in to undo is a proportion mistake - art hung too high, a rug two sizes too small, a walkway nobody can pass through - and this is the only title here organized around fixing exactly that. It is a reference first and a picture book a distant second, which is the right priority.
Pros
- Built around measurements and proportion rather than taste, so it answers questions a styling book cannot
- Illustrated by Mia Olofsson in clean line diagrams - you can see the rule, not just read it
- Works on any style of room, because geometry does not care whether you like farmhouse or modern
- Short enough at 240 pages to read end to end in a weekend and then use as a lookup for years
Cons
- Deliberately sparse on inspiration photography - if you want finished rooms to fall in love with, this is the wrong book
- Originally published in Swedish, and a few references sit closer to Scandinavian norms than American ones
- The 2020 publication date shows in the shopping references; the measurements and principles are unaffected











