Hosted by IPAC with support from the NASA Herschel and Spitzer Projects. This conference aims to explore the formation and evolution of galaxies using mostly gas tracers. Infrared and submillimeter observations gauge not only the quantity and distribution of gas in galaxies, but also the thermal and dynamical state of its various phases. Star formation and feedback involve physics that can be constrained with long wavelength observations: photoelectric heating, UV excitation, turbulence, cosmic rays, shock waves, atomic and molecular line emission, and thermal emission from dust. The conference will begin with what we know about the physical conditions of gas in the nearby universe out to z = 1, and then push outwards to earlier epochs when galaxies were forming most of their stars. Among the topics under discussion will be the mystery of dark gas, the conditions of gas in both isolated and interacting galaxies, and the role of gas in the origin of the galaxy main sequence. As we explore the results from current facilities, we hope to lay the groundwork for understanding future observations of gas and dust.