One of the standard histories of that dark period of Byzantine Empire following the conquest and sack of Constantinople by the Fourth Crusade in 1204 up to Michael Palaeologus's recovery of that city in 1261. As can be expected for a book written before WWI, Gardiner covers the actions, movements, and viewpoints of the rulers and elite, but pays slight attention to the social changes in the background. Includes a brief sampling of primary sources in translation as an appendix.