I am 73 years old and happily married, but I recently fell in love—not with an actual person but with a fictional character. This sort of thing hasn’t happened since high school, when Heathcliff inflamed my adolescent imagination. But now, after a lifetime of reading, I find myself besotted by Lord Peter Wimsey, the amateur detective of uncanny insight and resourcefulness who figures in 11 novels and numerous stories by Dorothy L. Sayers.