Chloroplast research takes significant advantage of genomics and genome sequencing, and a new picture is emerging of how the chloroplast functions and communicates with other cellular compartments. In terms of evolution, it is now known that only a fraction of the many proteins of cyanobacterial origin were rerouted to higher plant plastids. Reverse genetics and novel mutant screens are providing a growing catalogue of chloroplast protein-function relationships, and the characterization of plastid-to-nucleus signalling mutants reveals cell-organelle interactions. Recent advances in transcriptomics and proteomics of the chloroplast make this organelle one of the best understood of all plant cell compartments.