Arabidopsis thaliana has the distinction of being the first plant to have its genome sequenced. Before the genomics age, Arabidopsis was the model organism of choice for a large community of plant biologists. The small size of the genome and the availability of well established genetic resources enabled the use of mapped-based cloning to isolate and characterize genes well before the availability of a sequenced genome. At the present time, Arabidopsis still remains the organism of choice for many researchers due to the vast amount of genomic, proteomic, and many other “omics” resources that allow researchers to investigate many facets of plant biology.