Omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) display beneficial actions in human diseases. The molecular basis for these actions remains of interest. We recently identified novel mediators generated from ω-3 PUFA during Cell-Cell interactions that displayed potent anti-inflammatory and proresolving actions. Compounds derived from EPA are designated r esolv ins of the E series (RvE1), and those biosynthesized from DHA are denoted r esolv ins of the D series (RvD) and docosatriene, such as protectin D1 (PD1), which belongs to the family of protectins. In addition, treatment using aspirin initiates a related epimeric series by triggering endogenous formation of the 17R-RvD series, denoted as aspirin-triggered (AT)-RvDs. These compounds possess potent anti-inflammatory actions in vivo that essentially are equivalent to their counterpart generated without aspirin, namely the 17S-RvDs. In this chapter, we provide an overview and detail protocols of the biosynthesis and bioactions of these newly uncovered pathways and products that include three distinct series: 18Rresolvins of the E series derived from EPA (i.e., RvE1); 17R-resolvins of the D series from DHA (AT-RvD1 through RvD4); and 17S-resolvins of the D series from DHA (RvD1 through RvD4).