Bulletin of the World Health Organization 2012;90:321-321. doi: 10.2471/BLT.12.000512 In the editorials of this special theme issue on e-health, Najeeb Al-Shorbaji & Antoine Geissbuhler (322) discuss how to establish an evidence base for e-health, while JEWC van Gemert-Pijnen et al. (323) look at ways to improve the credibility of e-health technologies. In the news section, Claire Keeton (326–327) examines ways of measuring e-health impact, while Michael Dumiak (328–329) looks into the future of e-health. In an interview, five leading e-health thinkers (330–331) debate key challenges in the field. http://www.who.int/bulletin/volumes/90/5/12-000512/en/index.html