Complex sentence: The Captain of the "City of Baghdad", J. Armstrong White, later wrote the foreword to "Atlantis, the Story of a German Surface Raider" written by U. Mohr & A.V. Sellwood.
Split into simpler sentences: The Captain of the "City of Baghdad" was Captain J. Armstrong White. He wrote the foreword of "Atlantis, The story of a German Surface Raider" written by U. Mohr & A.V. Sellwood.