EBONI (Electronic Books ON-screen Interface) [1] builds on the premise to emerge from the Visual Book [2] and WEB Book projects [3], that appearance is important in the design of electronic textbooks, and offers an evaluation model, or general methodology, from which ebook usability experiments in a range of areas can be extracted and remain comparable at a basic level. The methodology sets out options for selecting material, participants, tasks and techniques, which vary in cost and level of sophistication. Results from each study will feed into a set of best practice guidelines for producing electronic textbooks on the Web, reflecting the requirements of students and academics throughout the UK.