I just finished reading Håkon Wium Lie thesis, Cascading Style Sheets; Håkon, apart from being the CTO of Opera, is one of the main contributors, and a vocal proponent, of the CSS effort at W3C. Håkon and Bert Boss co-authored the CSS1 specification and (some of) CSS 2.1 specification. His thesis is, in many ways, an important historical account of how Cascading Style Sheets came to fruition – the thesis traces significant historical moments, including significant discussions in W3C’s style mainling list, that brought about the CSS specifications. It also covers other relavant stylesheet proposals that influenced that current CSS specifications. In addition, his thesis outlines some of the important differences between print-centric style sheets and screen-centric style sheets, as well as the specific requirements that a style sheet language needs to be suitable for the web. The rest of the entry tries summarise Håkon’s thesis and how it relates to rich application development.