There are a number of free and paid text editors on the market. The screenshots in this training will be from oXygen XML editor, a paid tool that is really useful for editing EPUBs as it opens and closes them without zipping and unzipping, it validates HTML, CSS, and the EPUB itself on the fly, and has powerful RegEx find/replace capabilities. The interface is quite sophisticated, which may be offputting to people who are new to editing code.
