In July 1917 — the point at which Miranda Carter opens this enterprising his­tory of imperial vicissitudes and royal reversals — George V, king of Great Britain and emperor of India, resolved to change his name. In that scorching summer, King George was a worried man. His Russian cousin, Czar Nicholas II, had recently lost his throne and was under house arrest. In Germany, another imperial cousin, Wilhelm II, had been stripped of his proudest title, “supreme warlord.” Deprived of power, Wilhelm discovered a hitherto absent sense of humor. Hearing that the English king had decided to bury his German connections by proclaiming himself a member of the newly formed House of Windsor, the emperor pondered the possibilities for a forthcoming Shakespearean production: “The Merry Wives of Saxe-Coburg-Gotha.”

George V also attempted lightheartedness in the face of adversity. Accused by H. G. Wells of presiding over an “alien and uninspiring court,” the king retorted that while he might be uninspiring, “I be damned if I’m an alien.” But, as Carter takes care to remind us, King George was as alien in England as was his German cousin. It had been their grandmother, the half-German Victoria, who had conspired with their entirely German grandfather, Albert, to swamp (and thereby unify) Europe by planting members of their extensive family in every duchy, state and kingdom the House of Hanover might conceivably aspire to bring under control of the queen. This strategy, back in 1859 — the year Victoria and Albert’s eldest daughter gave birth in Prussia to the future kaiser — was the way the royal world worked. Intermarriage was seen as the key to sound international relations, and thus to international peace.

As we all know, the scheme failed spectacularly. The collapse of that grand dynastic plan, by which Britain could comfortably preside over (and exploit) an age of rapid technological progress and expanding international markets, provides the narrative structure for “George, Nicholas and Wilhelm: Three Royal Cousins and the Road to World War I.” Many historians have examined the prewar links between England and Germany; fewer have attempted to incorporate Russia, a major player in the conclusive defeat of Victoria’s dream of a royal, unified Europe.

Carter’s emphasis on the three cousins allows her to give full attention to Russia’s role in the story. Her difficulty is that the links between Nicholas, Wilhelm and George, whether in their character or in their personal relationships, are fragile. The friendship between them was, at best, tenuous. George and Nicholas exchanged emptily affable letters two or three times a year; the kaiser, meanwhile, charged in and out of their sedate courts like a runaway actor in search of a stage, blustering, boasting, seizing whatever limelight was available for his approval-hungry spirit.