Charles Oman's "The Dark Ages: 476-918".
Like his "Byzantine Empire", this is a broad historical overview of the titular subject, but unlike that book I didn't loathe the subject matter by the end.
The book starts off with the seemingly distinct event of "the fall of the Roman Empire", explaining right off that there was no such thing - more a petering out of the Western Emperors and a long, gradual waning of the Eastern Emperor's authority in the West. With the loss of authority in the West, and the Eastern Empire's deflection of the migrating Germanic tribes from its own lands, the history becomes dominated by the Ostrogoths, Visigoths, and Vandals - in descending order of their interest in preserving the civilization of which they'd taken possession.
Over time, as the Ostrogoths are worn down by the Eastern Empire and the infighting of their Latin subjects, they peter out and disappear from the scene, leaving space for the Burgundians, Lombards, and Franks to move in. The popes increase in power from powerful bishops under the authority of the Emperors to monarchs in their own right in response to the on/off power vacuum in Italy and the various theological controversies emanating from Constantinople. Unlike the Visigoths in Spain, the Franks gradually get their act together and begin unifying the Germanic tribes in response to outside threats (including the Islamic conquest, the Avars and Magyars pressing from the east, and the Saxons and Vikings pressing from the northwest), culminating in the reign of Charlemagne. Then they fuck it all up via the Teutonic tribal custom of dividing the realm among the male heirs, instead of passing the whole thing intact. A century of civil war and Viking invasion ensues, in which the familiar nations of Europe begin to emerge - France from Neustria and Aquitaine, the Low Countries (eventually) from the original Lotharingia, Germany from Austrasia, Bavaria, Thuringia, and Saxony, and (northern) Italy from Lombardy.
Like his Byzantine history, these were all things I'd known only the barest facts about from my public school education. Oman doesn't get very deep into any of what he covers (apart maybe from Charlemagne, whose reign is described from three different angles over three separate chapters), but instead surveys the entire period with enough depth to give the reader a sense of the historical structure and undercurrents - what happened and generally why - without getting bogged down. And since his writings predate the rise of Marxist academia, he does not subject the reader to tedious class-based analysis, cultural relativism, po-mo jargoneering, or pseudo-Freudian divining of motives seen in many modern histories. He is in fact refreshingly cynical at points about the characters of the individuals and peoples he describes.
One interesting insight from the book is how the Islamic conquest started and spread. It was all very rapid following the death of Mohammad, but it actually started in his lifetime with his letter of warning/invitation to the Byzantine and Persian emperors (then engaged in what would be the last of their incessant series of pointless border wars, which in this case weakened their ability to fend off the "opportunistic infection" of the Islamic war parties spreading out of Arabia). It spread out continually for three generations, leading to the conquest of Spain and only stopped by Charles Martel as it moved over the Pyrenees. But up until the end of the book's period of interest (actually the 940s despite 918 being in the title), the Christian West's response had mainly been to thwart Islamic progress, only rolling back the conquest here and there (the Spanish Marches that became Catalonia, for example, or the expulsion of the Muslims from parts of Benevento and Provence). He doesn't talk about the Crusades which came a century or so after this book concludes, but you can see the foundation for why they happened - they weren't some inexplicable and out-of-nowhere spasm of religious intolerance, a historical atrocity Christendom took on on a sadistic and murderous whim against their peace-loving and friendly-neighbor Muslims, but as a pushing back against a grave outside threat that had been advancing for three-plus centuries at that point. The fanatical Arab hordes of the early conquest period scared the bejeebus out of the rulers of Europe, and with good reason. They were anything but the powerless and innocent victims of Christian aggression typically portrayed in modern histories, which are saturated with a boring and shallow reductionist obsession with seeing every civilization and personality in history through the filter of Nazis-vs-Not-Nazis.
Worth reading. Not really a difficult or a long read, but neither is it insultingly written down to the 8th-grade reading level of the average modern reader.
RooshV.com