Molecular archaeology is the most innovative field within contemporary archaeological science. Archaeologists are no longer searching for the most obvious, durable evidence of the human past, but in the last ten years have moved on to detecting something more fragile and less visible - they are looking for what they can find in the molecules of organic tissues, particularly ancient DNA. The "Molecule Hunt" offers an overview of this new science, drawing on case studies and showing how dramatic developments in the tracing and decoding of DNA molecules have transformed archaeology.