Need advice/referrals for working with Executive Recruiters

[Anonymous]

I have managed to get pretty far in my career without ever working with a recruitment firm/executive recruiter. My field is somewhat specialized, but high enough in demand that I have never had problems getting jobs or getting promoted.

I want to go to the next level in my career and I'm at the point where I think a recruitment firm is essential. I think I've gone as far as I can go on my own.

Any advice on how to find a good recruiter, how to engage the search process with them, or other words of wisdom?
thanks