Invalid controls undermine conclusions of FDA studies.

This issue of Toxicological Sciences features several exciting changes: a redesigned cover, revised category subheadings, and this "Look Inside ToxSci" feature. Together with my esteemed colleagues in the field of green chemistry, we have outlined some exciting opportunities for the field of toxicology in the editorial on green chemistry and toxicology. There are insightful articles on the regulatory challenges regarding mixtures that are being addressed by the European Union and on risk assessment of carbon nanotubes. In the past, we have highlighted a single article from each issue. It has become increasingly difficult to select just one article from the volume of high quality work, so beginning this month we will highlight multiple articles in each issue here in "Look Inside ToxSci." From solvents, pesticides, and nanoparticles to the microbiome, the highlighted articles span the breadth of our field. Of course, this issue contains something that will never change; our raison d'etre …the best original research in the field of toxicology. -Gary W. Miller.