Books like The Discworld Companion
Terry Pratchett, Stephen Briggs
The Discworld Companion is 383 pages, about 7 hours 1 minute at 250 words a minute.
8 books to read next
How long each takes
The Book of Lost Tales [1/2] 5.7 h 
The Shaping of Middle-Earth 7.0 h 
Minor Arcana 5.3 h 
The Book of Lost Tales, Parts One & Two 6.6 h 
Understanding Audio 6.6 h 
The Mixing Engineer's Handbook 4.7 h 
The Lord of the Rings 2.6 h 
The Sorcerer's Companion 5.7 h Bar height shows length. Estimated at 250 words a minute.