For what it's worth, if you only go through the implementation of the tree-walk interpreter in Java, that's 234 pages. The next 370-ish pages are the C re-impl

For what it's worth, if you only go through the implementation of the tree-walk interpreter in Java, that's 234 pages. The next 370-ish pages are the C re-implementation as a bytecode interpreted language. So that adds a bunch more stuff to cover: actually compiling, bytecode interpretation, garbage collection, etc. Also, a huge chunk of it is code listings. Unlike other comparable books I've seen, Nystrom's doesn't skimp on the details, or make you go download the code from GitHub. Compared to how other books I've seen tend to do it, I'd argue that that's several hundred pages' worth of making the book quicker to read.