"The Sixth Extinction: An Unnatural History" is a book by Elizabeth Kolbert that explores the ongoing mass extinction of species caused by human activity. It discusses how factors like climate change, habitat destruction, and pollution are leading to the rapid decline of biodiversity on Earth. Kolbert presents scientific evidence and case studies to illustrate the impact of these changes on various ecosystems. The book is structured around Kolbert's travels to different locations, where she examines the effects of extinction firsthand. She highlights the role of scientists and conservationists in understanding and addressing these challenges, emphasizing the urgency of protecting endangered species and their habitats.