I'll do a roundup post on the entire Decline and Fall later in the weekend, but for now I just want to log that I have reached the end. The last two volumes of the original publication deal with the later Byzantine Empire, the rise of Islam, the Crusades and the final fall; the chapters are:

(Original Vol 5)
Chapter XLVIII: Plan of last two volumes, and later Byzantine emperors
Chapter XLIX: Iconoclasm, Charlemagne and the Holy Roman Empire
Chapter L: Mahomet
Chapter LI: the successors of Mahomet
Chapter LII: The limits of the early caliphate
Chapter LIII: The Byzantine Empire in the Tenth Century
Chapter LIV: The Paulicians and the Reformation
Chapter LV: The Bulgarians, the Hungarians and the Russians
Chapter LVI: Italy and the Normans
Chapter LVII: The Turks

(Original Vol 6)
Chapter LVIII: The First Crusade
Chapter LIX: The Later Crusades
Chapter LX: The Fourth Crusade
Chapter LXI: The Latin Empire, the Crusades and the Courtenays
Chapter LXII: the East in the later thirteenth century
Chapter LXIII: The East in the early 14th century
Chapter LXIV: Genghis Khan, and the return of the Turks
Chapter LXV: Tamerlane / Timour, and the Turks again
Chapter LXVI: The Eastern Empire and the Popes
Chapter LXVII: The Beginning of the End
Chapter LXVIII: The Fall of Constantinople
Chapter LXIX: Rome, 1100-1300
Chapter LXX: Rome, 1300-1590
Chapter LXXI: The End

Whew.