I wavered between rating this anthology four or five stars.  As with most anthologies, it is uneven.  I liked some stories better than others.  At the end of the day, I went with the higher rating because my preferences were based more on genre than writing style; I tend not to read YA urban fantasy, for example (with a few notable exceptions like Charles de Lint).My favorites were Assassin's Keeper and Crop Circles, but all of them were well-done, using the "key" theme in different and sometimes unexpected ways.