This book captivated me for the first two-thirds, and then somewhere along the line I grew tired of what I once loved about it. I think I sensed that it would not satisfy the mysteries it set up. The novel has a bit of everything: natural science, art, mystery, psychological thrills, trauma, memory, interpersonal connections (and the lack thereof). In the end, it's trying to be a bit too much, and not all the elements came together for me.
The protagonist is Miranda, a photographer who lost her mom at 14. The book begins at the end, with Miranda leaving the Farallon Islands off the coast of California; she's spent about a year in this dangerous place with rough terrain and rougher wildlife. living with a bunch of biologists, most of whom aren't the friendliest. It's a place she's come to love, but in the beginning, all you sense is that she's escaping some danger or trauma. The rest of the book is told through letters she writes to her dead mother.
Geni's prose can be gorgeous, but by the end it also becomes tedious. There are only so many descriptions of the ocean and horizon one needs. Some similes don't feel right tonally for what's being described. Other times, specific details are repeated needlessly. However, for much of the book I appreciated the language, and it's one of the reasons I decided on three and a half stars versus only three.
Acts of violence begin occurring on the islands over the course of Miranda's stay. Some are clearly not accidents, while others remain mysterious, whether the nature of the violence or who's responsible. In this way, the book sets up at least one set of mysteries. Many of these and other mysteries are somewhat predictable in their resolution, even if I was temporarily distracted by other options.
The title refers to two kinds of people who've populated the islands in the past--the light(house)keepers and eggers. The latter ransacked the islands to make money off murre eggs when there weren't many chickens yet in California. The lightkeepers only wanted to protect the islands by non-interference. There's a moment when this is the division that apparently characterizes any one person: you're either a lightkeeper or egger. This felt trite and unnecessary to me, though besides the prose I'd say the degree of the characters' noninterference--and its potential cost--was the most interesting aspect of the story.
The book also ends with a coda from another character's pov that explains just about everything. Perhaps it's meant to be haunting and shocking, but it felt anticlimactic to me. I'm not sure what I wanted from this book by the end, but I didn't get it.