RNA bioinformatics and computational RNA biology have emerged from implementing methods for predicting the secondary structure of single sequences. The field has evolved to exploit multiple sequences to take evolutionary information into account, such as compensating (and structure preserving) base changes. These methods have been developed further and applied for computational screens of genomic sequence. Furthermore, a number of additional directions have emerged. These include methods to search for RNA 3D structure, RNA-RNA interactions, and design of interfering RNAs (RNAi) as well as methods for interactions between RNA and proteins.Here, we introduce the basic concepts of predicting RNA secondary structure relevant to the further analyses of RNA sequences. We also provide pointers to methods addressing various aspects of RNA bioinformatics and computational RNA biology.