Carl Sagan books in order
18 books in the catalogue, about 117 hours of reading in all; the shortest takes 3 hours and the longest 9 hours.
18 standalone books in the catalogue.
Standalone books
Intelligent Life in the Universe 9.3 h 
Planets 3.7 h 
UFO's 5.7 h 
The Cosmic Connection 5.0 h 
The Dragons of Eden 5.0 h 
Murmurs of Earth 5.0 h 
Broca's Brain 7.3 h 
Cosmos 6.5 h 
Creations 6.4 h 
Comet 7.3 h 
Contact 7.9 h 
A Path Here No Man Thought 8.5 h 
Shadows of Forgotten Ancestors 9.3 h 
Pale Blue Dot 7.9 h 
The Demon-Haunted World 8.7 h 
Billions and Billions 5.4 h 
Conversations with Carl Sagan 3.1 h 
The Varieties of Scientific Experience 5.5 h