This volume is a compilation of the lectures at TASI 2012, held in Boulder, Colorado, June 2012. The program comprises two parallel lecture series on particle physics and on cosmology. The particle physics lectures covers LHC related experimental techniques, phenomenology, as well as basics in physics beyond the standard model. The Cosmology series give a general introduction to modern cosmology with special attention to the topics of dark matter, the microwave background and alternatives to the standard model of cosmology. The lectures are accessible to graduate students at the initial stages of their research careers.