IMO the better approach, given how dynamic and fast-moving development is, is to put this kind of information directly into the image. Pharo even already has a mechanism for authoring tutorials and it has an example tutorial using that mechanism, but I wish there was just more to that content that covered the material in the books/MOOC.

The reason is then hopefully the documentation stays aligned with the state of the particular image you're working with rather than hoping some volunteer has updated a book for the particular version of Pharo you're using.

I took a stab at doing this myself, but I was learning as I went and eventually ran out of gas since writing Pharo tutorials didn't beat other stuff on my personal priority list.