The z-book project aims to resolve the contradiction between thinking in a structured way but using a linear flow of text to transfer knowledge. The lack of unity of content and form makes it difficult to understand and absorb the subject. In this project, we have developed a visual language for communicating complex knowledge, with a structure that matches that of human models of thinking and memorisation as established by cognitive psychology. We used a new writing support, a zoomable virtual canvas, and other computer visualisation techniques.

We have defined the principles of z-book editing and based on this, we have developed a prototype on anatomy in collaboration with the Medical University of Heidelberg and Inova. The prototype was tested with students at the university. The first usability tests proved that students can use the zoomable map-like tool in a natural way without a user manual.

The prototype was offered to a whole cohort to prepare for the exam, but during the overcrowded period only a few students took the risk of learning with a tool that was unfamiliar to them. Due to strict conditions imposed by the university's Ethics Committee, we were unable to contact the participants directly. We received mostly positive feedback and some critical comments through completed questionnaires. Based on these responses, consultations with the trainers and our own observations after use, we have further developed the prototype in terms of content and technical aspects.

In the second experiment, the university tried to involve more students, but even here the number was not sufficient for a validation of scientific value. 16 students prepared for the exams with the z-book. The average of their exam results was the same as the average of the others. The time spent on preparation could not be compared. Tracking the z-book users showed that they spent between 30 and 116 minutes studying the material. The content of the prototype is equivalent to that of a 33-page traditional textbook, which covers 202 anatomical concepts in detail. The average of 72 minutes spent studying it is considered effective.

After the experiment, we had the opportunity to interview five students and two instructors and to study four completed questionnaires. With the exception of one questionnaire response, positive feedback was received. The participants recognised the benefits of the z-book and the effective learning opportunities. They would like to use z-books in the future and would recommend them to others. The interviewees provided many creative ideas for further development. The lecturers indicated that there is a serious problem of integrating disciplines in medical universities throughout Germany. For example, the links between anatomy, physiology and biochemistry are not well understood by students. The structure of the z-book is also seen as a suitable way of presenting these connections.

A further improvement could be to allow instructors to semi-automatically compile teaching notes in z-book format from the proliferating scientific ontologies. These could be used as a presentation tool by instructors. They could visually present the concepts of a subject area and their structure. Students could study the details in the same structure. We hypothesise that this would make the teaching-learning process based on a credible scientific basis and based on the didactic vision of the instructors most effective.