My favorite passage comes at the end of the first chapter (pages 23-25), comparing and contrasting the forms of doppelgänger used by three women, many centuries and thousands of miles apart, in order to explain and justify their unusual authority. The most difficult was required for a Chinese woman of notoriously humble ancestry. Her successful formula combined an obscure Buddhist sutra, describing a bodhisattva incarnated in an “instrumental” (but not real) female body, with a Confucian aphorism about the Mandate of Heaven falling on a “saint [who comes] from grass.” The resulting doctrine was preached by acolytes in special temples throughout her empire; two of their master texts have been preserved.Anohter favorite section (pages 36-40) describes the major unwritten rules governing female inheritance in European monarchies. Because formal political theory evaded the problem, these rules must be induced from surviving evidence. They were not obvious. Even Catherine the Great, attempting to draft rules of succession for the Russian Empire, could not find a formula that would justify her own rule. The most fundamental criterion, although almost never discussed specifically, turned out to be legitimate birth. In 1460, the last illegitimate male to acquire a European kingdom by overthrowing a younger but legitimate female sibling did so only with assistance from an Egyptian jihad.I’d also be happy if casual readers opened to the illustrations grouped after page 121. Originally I requested forty, but ended up with only seventeen. However, all of these carry politically-charged messages about how women rulers have been presented in ways emphasizing their authority across the 3500 years separating Hatshepsut and Margaret Thatcher.One of the most satisfying aspects of this book is that it has been possible to complete it at a time when one can combine old-fashioned historical research with the multiple resources available through the internet. I still explore a few dusty archives, read rare books in major western European languages, and inspect places in various countries that remain closely associated with long-ago women rulers. But I could never have sifted so much diverse written and pictorial information so efficiently without the internet.It has also proved extremely helpful that during my professional lifetime, English has become the standard or default language for scholars throughout Europe as well as in other parts of the world.In combination, these advantages offer optimum possibilities for deepening our comprehension of what these thirty women sovereigns could and could not do about commanding all-male political elites.Although Europe’s female monarchs were much likelier than their male counterparts to abandon their grip on sovereignty, this work interprets Europe’s overall experience of female rule as a glass that is half-full rather than half-empty, I expect it to spark controversy; the Republic of Letters usually requires dialectical processes in order to produce incremental improvements.I further realize that a 75-year-old man inevitably perceives many things differently from the mostly younger women who will probably comprise a majority of my readers. Nevertheless, I think being male helps me understand one vital problem about “female kings”: why were their orders routinely obeyed by entirely male political elites who had been conditioned to regard women as inherently inferior? My epiphany occurred on a transatlantic flight when a woman’s voice announced on the intercom, “This is your Captain speaking.” Captain is also a military rank, and every man on board knew that he should follow orders from someone with unquestionable credentials to call herself Captain Renée.