Executive recruiting is like any other profession in that you have The Good, The Bad & The Ugly. There are good, ethical and well-respected recruiting professionals. Unfortunately, you also still have bad and unethical and downright miscreants. As a potential candidate (and everyone is a potential candidate) it behooves you to know the differences between them.

Any good executive recruiter should be able to answer the basic Who, What, When and Where questions when they approach you as prospective candidate.

Who represents both their firm as well as their respective client. A professional recruiter should identify themselves, their company, and alert you to the nature of their call. They should also identify the client with which they are working. Be capable and willing to answer any questions regarding their own firm and their respective clients firm.
 
What applies to the opportunities description. A good recruiter will provide you with an outline of the position which would include minimum requirements, responsibilities, amount of travel, company reporting structure.

When & Where relates to the urgency of filling the position. Typically, once a recruiter is involved this represents an immediate need for the hiring Client. And where is the location of the company and respective opportunity.

When an executive recruiter is unwilling or unable to answer the basic four questions, it is time to run and find a true professional recruiter. One that is an expert in your field.