With coverage for wavelengths ranging from 21 cm to 2.6 mm, the ngVLA will enable break-through science in galaxy evolution. It is designed to provide order-of-magnitude improvements in depth and area for surveys of cold gas in galaxies back to early cosmic epochs, and it will enable routine sub-kiloparsec scale resolution imaging of the gas reservoirs. The ngVLA will afford a unique view of how gas enters and leaves galaxies and how it is transformed inside galaxies. It will also be capable of surveying the physical and chemical properties of molecular gas over the entire local galaxy population. Studies with the ngVLA will reveal the detailed physical conditions of gas in present day galaxies, and allow us to follow the gas during galaxy assembly and evolution throughout the history of the universe.