Richard Quebedeaux's study of the growth of the charismatic movement in the U.S.

Until the 1960s and 1970s, there was a fairly large gulf in American Christianity between Pentacostal denominations (such as the Assemblies of God) and mainline denominations (such as the Roman Catholic, Methodist, Presbyterian, and Episcopal churches). However, by the mid-70's it was clear that practices such as speaking in tongues and faith healing has spread among mainline church members.