The Natural World Book Prize was an award organised by The Wildlife Trusts, and presented to recognise environmental literature. Considered the premier environmental book prize in the UK, it was sometimes referred to as the 'green Booker'. It was formerly known as the BP Natural World Book Prize (after its sponsor, BP), and in origin it was a merging of two previous awards, BP's Sir Peter Kent Book Prize, and a competition run by The Natural World, the magazine of the Wildlife Trusts.