The term "first lady" didn't make it into a dictionary until 1935. The earliest presidents' wives were called "Presidentress" or "Mrs. President," or often were simply ignored. Dolley Madison was the first to bear the title (in a play long after her death). Jacqueline Kennedy forbade her staff to ever use the appelation, reportedly deeming the term more appropriate for a saddle horse. Today, for better or worse, the term and the institution of First Lady are integral--though still evolving--aspects of our political and cultural landscape, and this is the first full treatment of the subject. Covering all 37 women from Martha Washington to Nancy Reagan (counting is complicated by the fact that daughters, daughters-in-law, and sisters of presidents were sometimes pressed into service), the...