Hi, To my knowledge, the Wiki currently used is not hierarchical. This means long page names and also seems inappropriate for "artificial hierarchies" that are too deep. I question the value of hints for the exercises. I think it's more productive and thought-provoking to solve an exercise without any hints. I recall frustrating moments during some of the exercises, but that's what good exercises should do. I think an answers book is a good idea. In my mind, its purpose is to allow people who have already solved an exercise to compare their solutions to other people's. It's interesting for me to make that comparison. I encourage people to contribute their solutions. I hope to see that all exercises are solved - in many different ways. Ariel