These books are omnibus editions, collections containing two or more novels and/or anthologies by Harry Turtledove. All the material in these books had been published prior to the publication of the omnibuses themselves.
“The Tale of Krispos (Del Rey, 2008) is an omnibus volume which collects Krispos Rising, Krispos...The Tale of Krispos
“The Time of Troubles I (Baen, 2005) is an omnibus edition collecting the Videssos Series novels...The Time of Troubles I
“The Time of Troubles II (Baen, 2005) is an omnibus containing The Thousand Cities and Videssos...The Time of Troubles II