2014 marks Cell's 40th anniversary, and over the year we have looked back at how discoveries of the last four decades have molded our understanding of biology. The final decade of the Cell Line features a selection of the exceptional scientific work-both landmark papers and essential reviews. Select entries can be read as an "Annotated Classic," which includes the original paper and accompanying reflections of a leading scientist, considering the work from our current vantage point. Our last installment includes a harbinger of the interplay between microbiota and mammalian hosts in 2004, revolutionary papers in 2006 and 2007 unlocking cellular reprogramming, the discovery of beige adipocytes in 2012, and the first example of CRISPR-based genome editing in a nonhuman primate in 2014. In addition to landmark publications, there were innovative developments at the journal in this decade, with the complete redesign of the print journal and the creation of Leading Edge in late 2005 and the restructuring of the online display of the article in 2010. Keeping pace with the changing nature of biological research, over the decade Cell added new article types, introduced guidelines for the organization of supplementary material, and expanded the journal's web-based content to bring editors' and authors' excitement and perspective on individual papers to the readership. An interactive version of the timeline, with links to the papers, full author lists, and Annotated Classics, is available at http://dx.doi.org/10.1016/j.cell.2014.11.004.