I have seen a lot of "body language experts" market themselves very effectively within the media. They are highly paid consultants who train companies and organizations, conduct keynote speeches and dazzle people at sales conferences, and even train agents within the federal alphabet soup (FBI, CIA, DOD, DHS, etc...). But as it turns out, many of them may be more experts on marketing than on body language. For me, a true expert should be someone who has done what they are teaching, not simply studied or read about it and reorganized the material into their own courses. I know that most dictionaries define an expert as "a person who has a comprehensive and authoritative knowledge of or skill in a particular area." My belief is that within the definition of expert the "or" should be change to "and", and that their skill should be tested in the real world, with real people and with real lives and consequences on the line. When hiring someone as a consultant or trainer for your company or agency, or if you bring them in for a keynote presentation, make sure they have the background of doing what they plan on teaching or assisting you with if you want real results.