By Harry Turtledove
Published by Ballantine Books:

THE GUNS OF THE SOUTH

THE WORLDWAR SAGA
WORLDWAR: IN THE BALANCE
WORLDWAR: TILTING THE BALANCE
WORLDWAR: UPSETTING THE BALANCE
WORLDWAR: STRIKING THE BALANCE

COLONIZATION
COLONIZATION: SECOND CONTACT
COLONIZATION: DOWN TO EARTH
COLONIZATION: AFTERSHOCKS

HOMEWARD BOUND

THE VIDESSOS CYCLE
THE MISPLACED LEGION
AN EMPEROR FOR THE LEGION
THE LEGION OF VIDESSOS
SWORDS OF THE LEGION

THE TALE OF KRISPOS
KRISPOS RISING
KRISPOS OF VIDESSOS
KRISPOS THE EMPEROR

A WORLD OF DIFFERENCE
DEPARTURES

HOW FEW REMAIN

THE GREAT WAR
THE GREAT WAR: AMERICAN FRONT
THE GREAT WAR: WALK IN HELL
THE GREAT WAR: BREAKTHROUGHS

AMERICAN EMPIRE
AMERICAN EMPIRE: BLOOD AND IRON
AMERICAN EMPIRE: THE CENTER CANNOT HOLD
AMERICAN EMPIRE: THE VICTORIOUS OPPOSITION

SETTLING ACCOUNTS
RETURN ENGAGEMENT