Books like The Neptune Project
Polly Holyoke
The Neptune Project is 341 pages, about 6 hours 15 minutes at 250 words a minute.
12 books to read next
How long each takes
Above World 6.6 h 
The Treasure of the Sea 5.7 h 
Maximum Ride Forever 7.5 h 
The Fire Eternal 9.4 h 
Roverandom 2.5 h 
The Drowned Cities 8.0 h 
The Fog Diver 6.0 h 
Dr. Franklin's Island 4.5 h 
Birthmarked 6.3 h Bodyguard 5.0 h 
Tess the Sea Turtle Fairy 1.5 h 
Way Down Deep in the Deep Blue Sea 35 min Bar height shows length. Estimated at 250 words a minute.