Planktonic organisms live in a world where viscosity, molecular diffusion, and thermal fluctuations dominate, a world outside the mainstream of ocean physics studies. The task of explaining the properties of this domain has fallen to talented biologists, such as Vogel (1981), Berg (1983), and Denny (1993), who provide intuitive understandings about it. Within the last year, two new books exploring the world of the small have arrived. The first, by Kiørboe (2008), has a strong emphasis on biological interactions, experimental tests, and oceanographic implications. The second, by David Dusenbery, published this year, emphasizes the physical nature of this realm.