First, it should be noted that Denis McQuail does not have just
one theory. He is a well-respected professor, researcher, and
author, and his best-known book is called "Mass Communication
Theory." It is now in a 6th edition, and is worth owning. In this
very thorough book, McQuail explains nearly every modern theory
about how mass communication occurs, and he also examines how mass
communication affects society. His own research is included: for
example, he discusses the role of politics and political rhetoric
in mass communication, how globalization has affected mass
communication, and the role of new media (including social media)
as a factor in what the public believes.