The term "Authentic Christianity" as it is used in so-called "Christian" books and magazines and blogs has nothing to do with authenticity or, very often, with Christianity for that matter. It has nothing to do with the truth and genuineness of the teachings proclaimed as "Christianity." Instead it has to do with the sincerity of an individual who self-identifies as "Christian." It has to do with with whether or not a person lives according to their own definition of what Christianity is or what they desire Christianity to be.
http://youtu.be/S5X_dF6cbtM - Pastor George Borghardt of Higher Things takes on the subject of "Faith" - what is it, what does it really mean to "believe in Jesus?" Watch this Higher Things video short and find out!