The author notes that there is no meta key anymore [1], however you can often setup your terminal emulator to use another key as the meta key.

In iTerm [2] I have the left alt/option key setup as meta, so things like meta-b are much easier to type then Esc-b.

[1] "You'll often see Meta+b but there is no such key on the keyboards anymore." [2] Profiles -> Keys "Left option acts as meta"