I recall that 14 years ago DHTML was the all the rage and javascript was the key to DHTML. So I took up JS and bought books and went in head first.
Conclusion: it was impossible to take that language seriously. Javascript was a hack.
So for me, the rise of javascript as anything more than a browser helper language has been very surprising. I still have some prejudice towards it. Maybe others feel the same way and knowing how O'Reilly comes from the UNIX tradition, I'm sure that's what they meant with that title.