Protein–RNA interactions play essential roles in gene regulation and RNA metabolism. While high-resolution structures have revealed principles of RNA recognition by individual RNA binding domains (RBDs), the presence of multiple RBDs in many eukaryotic proteins suggests additional modes of RNA recognition by combination and cooperation of these interactions. Recent structures, together with biochemical and biophysical studies have revealed novel principles of RNA recognition by multi-domain proteins. These examples highlight an important role for dynamics in RNA recognition, with mechanisms including fly-casting and conformational selection, and advocate the use of solution techniques for their analysis.