The beamer class: Controlling overlays

There was a question recently on the TEX StackEx-change site (Gil, 2014) about the details of how slide overlays work in the beamer class (Tantau, Wright, and Miletić, 2013). The question itself was about a particular input syntax, but it prompted me to think that a slightly more general examination of how overlays would be helpful to beamer users. A word of warning before I start: don’t overdo overlays! Having text or graphics appear or disappear on a slide can be useful but is easy to over-use. I’m going to focus on the mechanics here, but that doesn’t mean that they should be used in every beamer frame you create. 1 Overlay basics Before we get into the detail of how beamer deals with overlays, I’ll first give a bit of background to what they are. The beamer class is built around the idea of frames: \begin{frame} \frametitle{A title