The Death of Chaos by L. E. Modesitt, Jr.
Lerris has settled down as a carpenter in Kyphros, where his wife, Krystal, is the sub-commander of the autarch's military forces. His fellow apprentice from Recluce, Tamra, now travels with the Gray Wizard Justen. But the world is in turmoil, and not only from friction between the island of Recluce and the continent of Candar. For now the distant Empire of Hamor has sent invading forces across the ocean, as they have twice in the historic past - and this time they mean to conquer the world. Gradually, but ever more deeply, Lerris is drawn back into action and forced to exercise and strengthen his magical powers to become the greatest wizard of all time - or see his world destroyed. Find out more about this title and others at www.orbitbooks.co.uk