One of Ms. Barrett's best stories, "The Littoral Zone," tells of flora meeting fauna: a botanist and a zoologist fall in love one summer while doing marine biology research "between high and low watermarks where organisms struggled to adapt to the daily rhythm of immersion and exposure." This is what Jonathan and Ruby are doing as well, moving from simple collegiality toward a decision to leave their spouses and children and embark on a new life. When we see them 15 years later, the completeness of their union will depend to some extent on whether they can still believe that Jonathan actually assimilated the bit of Ruby's fingernail he nibbled and swallowed during their first night together. The scientist in each of them knows that keratin is indigestible; romantically and morally, they need to believe otherwise.