Who is Edith Carow from The Rise of Theodore Roosevelt and what is their importance?

Edith appears to be Roosevelt's first sweetheart, before he leaves for Harvard. However, his romance with Alice Lee quickly overshadows this original relationship.

Yet, about 22 moths after the death of Alice Lee, she once again appears in Roosevelt's life. This time, they enjoy a more mature romance. Edith brings sensibility to Roosevelt's impassioned life. She gains control of his precarious finances. Even Roosevelt admits to McKinley that he makes few decisions without the blessing of his second wife. After Alice's death, and increasingly after his remarriage, mentions of Alice disappear. Both Edith and Theodore work to erase references to her from family correspondence.