Following 17 years as a practicing surgeon, I have been a full-time epidemiologist since 1986, Professor of Cancer Epidemiology since 1990 and Department Chair at Uppsala University, Karolinska Institutet and Harvard School of Public Health 1994 through 2011. My research has had a strong focus on cancer etiology but has also included prognostic studies and numerous randomized trials. Besides working on NorTwinCan, I am currently involved in launching a large prospective cohort study in sub-Saharan Africa; I am the PI of a large case-control study of nasopharyngeal carcinoma in south eastern China; I have a part-time affiliation with the University of Oslo where our work is focused on colorectal cancer, particularly colonoscopy screening, surveillance of patients with colonic adenomas and quantification of their cancer risk. I also maintain a broad interest in prostate cancer with a new initiative to launch a randomized trial of different active surveillance strategies. Developing mobile phone based technologies for prevention of obesity, particularly among children and adolscents, is another strong interest.