This document discusses Kendo UI, a JavaScript framework for building interactive and mobile-friendly user interfaces. It notes that while many mature server-side technologies exist, modern browsers allow more to be done client-side. Kendo UI provides UI widgets, templates, and other features to build cross-platform applications using HTML5, CSS3, and JavaScript. It works with technologies like jQuery and plays well with others. The document also briefly discusses different types of web and mobile developers and their perspectives before inviting the reader to learn more about Kendo UI.