Slime is an ambiguous thing. It exists somewhere between a solid and liquid. It inspires revulsion even while it compels our fascination. It is a both a vehicle for pathogens and the strongest weapon in our immune system. Most of us know little about it and yet it is the substance on which our world turns. Slime exists at the interfaces of all things: between the different organs and layers in our bodies, and between the earth, water, and air in the environment. It is often produced in the fatal encounter between predator and prey, and it is a vital presence in the reproductive embrace between female and male. In this ground-breaking and fascinating book, Susanne Wedlich leads us on a scientific journey through the 3 billion year history of slime, from the part it played in the evolution of life on this planet to the way it might feature in the post-human future.