The Elixir ecosystem is very powerful from a learner’s standpoint. One can go to elixir-lang.org, read Programming Phoenix (I haven’t checked out Nerves yet…), and then learn Absinthe or learn Functional Web Development (or even stick with traditional REST).
These books thoroughly cover their technology, effectively getting the reader up to an intermediate-level knowledge. The gap is when one finishes the book. The code-as-you-go project is designed to teach you the tech–hence it optimizes for breadth.
I would suggest some follow-up project guides that allow one to explore certain features in greater depth and apply other knowledge floating around the Elixir ecosystem.
For anyone else who has done a coding bootcamp, they teach predominantly through projects. You learn a new concept, and then apply it to a project for the rest of the day.
Ready-made project guides are what allow a new Elixir developer to (1) build a portfolio of work, while (2) getting as much learning out of the work one does as possible.
These guides can be as minimal as specs that define an architecture, and then point the user to resources with the instructions to use the technologies (i.e. these authoritative books that already exist).
This class of guides would abstract one’s learning from the book to a new, but similar project, allow one to recognize slight differences between the projects, giving one a sense of what else one can explore from there.
More feature-focused project guides would offer the depth that the authoritative books lack.
In this way, the community can produce significantly more learning resources than just the creators’ books. The book acts as the core, and the guides extend it.