This open access book presents interviews with high-profile climate scientists about state-of-the-art research questions. Consequences of climate change have become more and more visible and are now regularly discussed in political and societal debates. While climate scientists have been warning about potential consequences of anthropogenic greenhouse gas emissions for decades, their call for action has not sufficiently been heard for long. Meanwhile, the field of climate science has grown significantly and become more interdisciplinary. As a result, more sophisticated technologies, higher data availability as well as more advanced climate models have made the fundamental message stronger than ever: The impact of human activity on the Earth’s climate is clear and severe and irreversible consequences already occur all over the world. The authors were given the opportunity to talk to leading climate scientists from different disciplines. These do not only include theoretical physics, paleo-research, and climate modelling, but also cover the role of the biosphere, extreme weather events, and attribution science. Additionally, the interviews also address the political dimension of climate science.