Harry Turtledove books in order
29 books in the catalogue, about 259 hours of reading in all; the shortest takes 5 hours and the longest 12 hours.
7 series and 8 standalone books in the catalogue.
Worldwar
5 books 1 
Worldwar: In the Balance 9.9 h 2 
Worldwar: Tilting the Balance 9.1 h 
Homeward Bound 11.0 h
Worldwar: In the Balance 9.9 h 2 Worldwar: Tilting the Balance 9.1 h 3 Worldwar: Upsetting the Balance length not known
4 Worldwar: Striking the Balance length not known
Homeward Bound 11.0 h Settling Accounts
2 books
American Empire
3 books
The War That Came Early
6 books
Great War
2 books 1 
The Great War: American Front 9.3 h
The Great War: American Front 9.3 h 3 The Great War: Breakthroughs length not known
Crosstime Traffic
6 books Gunpowder Empire length not known
Curious Notions 5.0 h In High Places length not known
The Disunited States of America 5.3 h The Gladiator length not known
The Valley-Westside War 5.3 h Darkness
6 books 1 
Into the Darkness 11.4 h 
Jaws of Darkness 10.6 h 6 
Out of the Darkness 12.2 h
Into the Darkness 11.4 h 2 Darkness Descending length not known
3 Through the Darkness length not known
4 Rulers of the Darkness length not known
5 Jaws of Darkness 10.6 h 6 Out of the Darkness 12.2 h 
