This book is an "autobiographical" account of the life of Elizabeth I, Queen of England, and for me, this book is Elizabeth.
Miles just hits the perfect tone for the character. A little vain, but fiercely proud. Incredibly intelligent, but haunted and hunted by her own family. Susceptible to the love of men, but ultimately willing to sacrifice that love for her love of her country. It's just everything I ever imagined Elizabeth I to be.
Truly, if you're just going to read one book from this period, this is the one. (Yes, yes--even better than The Other Boleyn Girl.)