I found this book very helpful as a supplement to "Crafting Interpreters". The BEAM has a lot of interesting features that many mainstream languages don't. I found the parts about processes, tagging, memory and reduction counting (chapters 3-5 and 11) especially interesting.<p>The book is clearly very unfinished still, but what exists is very good. Got my mind spinning on what a good statically typed language running on a VM could look like.