The `IFindsBy*` interfaces (`IFindsByXPath`, `IFindsByCssSelector`, etc.) had been marked deprecated for some time, meaning that the methods defined by those interfaces (`FindElementByXPath`, `FindElementByCssSelector`, etc.) had also been marked as deprecated. A refactor of the class hierarchy during the 4.0 beta time frame meant that the deprecation had finally come to pass, and these methods were no longer available on driver classes. The examples you're following are outdated; you should be using the `FindElement` or `FindElements` methods, which take a `By` object as their argument. Contrary to your assertion in your post here, those methods most assuredly _are_ available; I've validated that by looking at the assembly using ILDASM, just in case something in the build process for the release had gone horribly wrong.