Like any other professional, as a career counselor, it's important for me to keep up with what's happening in my field. I do this by reading and studying and talking with thought leaders I respect.
I also periodically take a look at what the general public is reading by perusing the career shelves of bookstores.
I rarely buy these books because they tend to repeat things I already know and because, in the vast majority of cases, they present an approach I consider to be ineffective and outdated.