Understanding human heart development is crucial for tackling congenital heart disease, but a comprehensive reference dataset for certain periods of development has been lacking. Now, De Bono and colleagues present a powerful atlas of human heart development between 8.4 and 10.7 post-conception weeks. We spoke to first author Christopher De Bono, and to co-corresponding authors Stéphane Zaffran and Heather Etchevers (Team Leaders at Marseille Medical Genetics in Aix Marseille University, France) to find out more.