Biofilms are surface-attached microbial communities. Recently, my laboratory has begun to explore the question of whether or not microbes “know” they have engaged a surface. In this seminar I will present a series of studies that implicates a role for the type IV pili and the cell surface-associated protein PilY1 as critical for the upregulation of cAMP and cyclic-di-GMP, respectively, upon surface contact. cAMP and cyclic-di-GMP are key signaling molecules regulating the planktonic-to-biofilm transition. Our data reveal two surprising findings regarding how Pseudomonas aeruginosa initiates biofilm formation: (i) evidence for multigeneration bacterial “memory” triggered by initial surface contact, and (ii) a role for eukaryotic-like mechanosenory domain in the subsequent transition to a sessile community. Our work, and the efforts of our collaborators, use a combination of genetics, imaging and modeling to explore the complexities of transitioning from a free-swimming, planktonic existence to life on a surface.