State of Wonder by Anne Patchett

I have been told how amazing Patchett is, but never got round to reading her work until now. Since finishing this astonishing adventure, I've ordered her entire back catalogue. I cannot recommend State of Wonder enough. It has everything. Setting, characters, tension, mystery, romance. A new favourite book and go to author.

From the back

There were people on the banks of the river.

Among the tangled waterways and giant anacondas of the Brazilian Rio Negro, an enigmatic scientist is developing a drug that could alter the lives of women for ever. Dr Annick Swenson's work is shrouded in mystery; she refuses to report on her progress, especially to her investors, whose patience is fast running out. Anders Eckman, a mild-mannered lab researcher, is sent to investigate.

A curt letter reporting his untimely death is all that returns.

Now Marina Singh, Anders' colleague and once a student of the mighty Dr Swenson, is their last hope. Compelled by the pleas of Anders's wife, Marina leaves the snowy plains of Minnesota and retraces her friend's steps into the heart of the South American darkness, determined to track down Dr. Swenson and uncover the secrets being jealously guarded among the remotest tribes of the rainforest.

What Marina does not yet know is that, in this ancient corner of the jungle, where the muddy waters and susurrating grasses hide countless unknown perils and temptations, she will face challenges beyond her wildest imagination.

Marina is no longer the student, but only time will tell if she has learnt enough.