Books like First Warning
Anne McCaffrey, Elizabeth Ann Scarborough
First Warning is 371 pages, about 6 hours 48 minutes at 250 words a minute.
12 books to read next
How long each takes
White Oleander 7.2 h 
Among Others 6.5 h 
Rama II 9.1 h 
Deliverer 6.6 h 
The Last Man 7.8 h 
Divine By Blood 7.3 h 
The High Crusade 3.5 h 
Shadows in Flight 4.1 h 
North and South 8.4 h 
When Worlds Collide 6.3 h 
The Last Sin Eater 6.1 h 
Sargasso of Space 3.5 h Bar height shows length. Estimated at 250 words a minute.