Dr Helen Scales is a freelance writer, broadcaster and marine biologist based in Cambridge. Her doctorate involved searching for giant, endangered fish in Borneo; she’s also tagged sharks in California, once spent a year cataloguing all the marine life she could find surrounding a hundred islands in the Andaman Sea and recently returned from an expedition into the mangrove forests of Madagascar.

Her writing has appeared in the Guardian, BBC Wildlife Magazine, Natural History Magazine and National Geographic News. She appears frequently on BBC Radio 4, Sky News and the BBC World Service, and has presented BBC documentaries on topics such as whether people will ever live underwater, the science of making and surfing waves and the intricacies of sharks’ minds. She is also scientific advisor to the charity Sea Changers, a fellow of the Royal Geographical Society and a tutor at the University of Cambridge.

Her latest book, Spirals in Time, examines the secret life and curious afterlife of seashells and was adapted for BBC Radio 4’s Book of the Week.