The 8th CeMM Karl Landsteiner Lecture at the beautifully frescoed Festive Hall of the Austrian Academy of Sciences was delivered by Prof. David M. Sabatini of the Whitehead Institute for Biomedical Research of the Massachusetts Institute of Technology (MIT). More than 350 scientists and interested lay people from all walks of society attended the lecture, which was opened by CeMM’s Scientific Director Prof. Giulio Superti-Furga, who acknowledged Prof. Sabatini’s distinguished achievements and leading contribution to molecular biology. Gustav Ammerer, a Viennese biotech pioneer, research group leader at the Max F. Perutz Laboratories (MFPL) of the University of Vienna and accomplished amateur cello player provided a smooth start of the evening with his interpretations of Johann Sebastian Bach’s Suite No.1 in G major (BWV 1007), Allemande & Sarabande. David M. Sabatini continued the series of world-leading distinguished scientists of CeMM Karl Landsteiner lecturers that started in 2007. Prof. Sabatini, MD, PhD, recipient of the 2014 National Academy of Sciences Award in Molecular Biology, is the leading investigator on what can be considered probably the most “critical” biological process, the regulation of cellular growth and metabolic state, and its master regulator protein “mTOR” with its essential role in cellular decision making. In his talk “Grow – Shrink, Get Fat – Stay Lean, Divide – Rest: How Cells Decide” Prof. Sabatini outlined the fundamental and intriguing processes surrounding the mTOR protein that cells use to integrate internal and environmental cues such as nutrient availability to rationalize cellular decision making such as proliferation or differentiation. In his presentation he also introduced some of his latest research findings and discussed challenging open questions. The lecture was very well perceived as evidenced by a lively podium discussion and rounded up by a cocktail reception in the academy’s aula. We are grateful to Prof. Sabatini for his fascinating presentation.