"We believe that education must be available to everyone which means supporting the creation of free, open, and accessible educational resources. We are actively committed to increasing the accessibility and usability of the textbooks we produce. The web version of this resource has been designed with accessibility in mind by incorporating the following features: it has been optimized for people who use screen-reader technology; all content can be navigated using a keyboard; links, headings, and tables are formatted to work with screen readers; images have alt tags; and information is not conveyed by colour alone."