Their subject is Eleanor Fontaine, the author of several books on etiquette. To familiarize California with the woman, Aunt Monica assigns her Fontaine's Proper Letters for Proper Ladies which California finds to be difficult and tedious reading. But when California discovers that Aunt Monica's house is haunted with the spirit of the Eleanor and of a friendly dog, she begins to take a more active interest in the Fontaine's life.
Eleanor's ghost is very sensitive and seemingly unaware of her passing. Whenever California does something to let that fact slip, the ghost dematerializes (only to reappear some time later but always a few years younger than before). For researching the biography, the ghost proves very useful and makes California a great help to her aunt. But as it becomes younger and closer in age to California, it becomes a friend and confidante for an otherwise lonely child.
A quirky and charming story that defies easy generalization. California's abandonment is a heavy subject, but hardly the sole focus of the story, which also addresses grieving, hidden family history, and alcoholism. The supernatural themes are subtle and don't take the story too far away from realism. Throughout, California's innocent malapropisms and tendency to overshare provides numerous hilarious exchanges (most notably through the many letters that she writes, following a bit too literally the guidelines of Eleanor Fontaine).
Urban's Crooked Kind of Perfect is among my all-time favorite children's books. This one is not quite at that level, but is a superior book nonetheless.