This book started off well, with a bunch of attention-grabbing facts (who collected 2.5 million butterflies in his lifetime? find out!), but seemed to thin out factwise towards the end. As usual, Russell has a lovely, strong voice in her writing:
I can't believe they trust me, alone.
I sit at the table, waiting for David Carter.
Then I stand up, and sneak to the nearest drawer. [...]
I tiptoe down the wooden canyon, open two more drawers, three more, five more, an Owl, a Zebra Longwing, a Red Admiral. I leave them all open. The butterflies begin to stir, pushing their wings against the case, moving up, bright ghosts, through the glass into the air. (pp.152-153)
You will probably enjoy it quite a bit if you're an insect lover, and it has a fairly extensive bibliography at the end of (perhaps) more scholarly sources. However, I didn't think it was quite as well written as Hunger was.