Compared to genome, transcriptome, and proteome the term metabolome was coined much later, although studies focusing on the metabolome, of course, have been performed before that point. In 1998 Oliver et al. mentioned metabolome analysis in the context of functional genomics (Oliver et al., 1998) and Tweeddale et al. discussed the term with respect to the phenotype investigation of E. coli (Tweeddale et al., 1998).