by William B. Mair, Ines Alvarez-Garcia Aging affects us all, but we still do not know how the process evolves or if we can modulate its pace. This issue of PLOS Biology presents a Collection of articles that explores different aspects of aging, discussing what challenges still need to be overcome. Aging affects us all, but we still do not know how the process evolves or if we can modulate its pace. This Editorial presents a Collection of articles that explores different aspects of aging, discussing what challenges still need to be overcome.