The new mechanistic philosophy is divided into two largely disconnected projects. One deals with a metaphysical inquiry into how mechanisms relate to issues such as causation, capacities and levels of organization, while the other deals with epistemic issues related to the discovery of mechanisms and the intelligibility of mechanistic representations. Tudor Baetu explores and explains these projects, and shows how the gap between them can be bridged. His proposed account is compatible both with the assumptions and practices of experimental design in biological research, and with scientifically accepted interpretations of experimental results.