Much of our knowledge of the hydrodynamics of stellar oscillations is summarized in the now-classical article by Ledoux & Walraven in volume 51 of the Handbuch der Physik. It is from that article that I, and many others, first learned the subject. Most of what we have learned since, aside, perhaps, from what we have learned from nonlinear studies, derives from that work. Even today, what is written in that work is hardly out of date. It is not possible to do justice to even the most outstanding contents of Ledoux & Walraven’s article in a single talk, so I highlight some aspects of further developments that have been of more recent interest, trying to set them into a context of current understanding.