Spineless:The Science of Jellyfish and the Art of Growing a Backboneby Juli BerwaldRiverhead Books, 2017Science writer Juli Berwald's new book Spineless: The Science of Jellyfish and the Art of Growing a Backbone is a shape-shifting thing much like the medusa, the genus Chrysoara, the jellyfish it exhaustively and lovingly describes. It morphs with disarming ease from memoir complete with wacky characters, sharp dialogue, and unexpectedly touching moments to natural history infused with curiosity and no small degree of wonder. It reads like some offbeat cousin of Helen MacDonald's H is for Hawk and Sy Montgomery's The Soul of the Octopus, and yet it's entirely and oddly its own being – and it even possesses the sting of its oceanic spirit animal: enormous jellyfish “blooms” in recent years are as inexplicable as they are important, clogging international fisheries and casting writhing, iridescent clouds over entire ecosystems.At the center of all this personal and ecological drama is a creature scarcely better understood by modern science than it was by Aristotle curiously picking his way through tidal pools in the middle of the afternoon two thousand years ago. When she's writing about them, Berwald is clearly enraptured and trying hard to keep that under control:

They have no centralized brain, but they see and feel and react to their environment in complex ways. Their body form looks simple, yet their swimming ability is the most economical in the animal kingdom. We know them in their swimming medusa form, but they live as much or more of their lives in a mysterious tiny tube planted on the underside of a rock. They wash ashore in hordes and they dominate the deepest depths of our planet, supporting entire ecosystems. And still, scientists are unable to predict where and when to find them.

Spineless follows her adventures as she travels through all the strange precincts of the jellyfish world, from the creatures in laboratory conditions (including the ones she begins to keep in her home), to the creatures in the wild, to the men and women who study them, harvest them, prepare them as delicacies, and look to them as bellwethers of the planet's rapidly changing oceans. Thanks to Berwald's considerable dramatist's skills, the resulting narrative ends up as a very winning combination of panoramic and personal. And it always comes back to the very strange animal at the heart of its story, which spends large chunks of its life in a form most people wouldn't recognize:

The fertilized egg grows into a larva, called a planula, that one jellyfish scientist aptly described as looking like a furry Tic Tac. The fur is a rug of eyelash-like extensions called cilia. Once a newly minted larva has its cilia wiggling, it starts swimming. Upon bumping into a rock or a dock or a boat hull – or in the lab, a Petri dish – it performs a spiral dance that ends when it attaches itself to the surface. And then, like an enchanted creature, it begins shape-shifting. The larva elongates into a tube and grows wispy tentacles. It builds a digestive tract down the middle of the tube and a mouth in the middle of the tentacles. This being is now called a polyp. Unlike human infancy, the polyp is not a brief stage that the jellyfish passes through. A jellyfish polyp is a fully realized organism. The jellyfish can be a polyp for much longer than it is the more familiar medusa. The length of time varies for different species. Some jellyfish probably remain polyps for years.

The “jellyfish journey” of Spineless is strange and ultimately quite charming, and all without sacrificing the rigor and dispatch of a scientist looking at a world poised on the brink of what could be catastrophic changes. Readers will never think about the strange medusa in simple terms again.