Books like At the Earth's Core
Edgar Rice Burroughs
At the Earth's Core is 152 pages, about 2 hours 47 minutes at 250 words a minute.
12 books to read next
How long each takes
Star Born 3.1 h 
Little Fuzzy 2.8 h 
The Complete Life and Adventures of Santa Claus 1.8 h 
The War of the Worlds 3.8 h 
What Makes Day and Night 35 min 
Dragonflight 5.7 h 
The Time Traders 3.2 h 
The Invasion 3.5 h 
The Last Battle 3.5 h 
The Silver Chair 4.0 h 
Pretty Monsters 7.5 h 
The Visitor 3.5 h Bar height shows length. Estimated at 250 words a minute.