What is the author's style in Hell House by Richard Matheson?

Hell House is written in straightforward English language. There is little in the way of scientific references but for one chapter describing both the Reversor built to Lionel Barrett`s specifications, and his beliefs regarding the human spirit and what remains after death. There is much made of the use of mind control, of the power of evil and of the lasting ability of one spirit to infect and afflict others. Some discussion of Spiritualists, and Mediums comes into play, but none of it is confusing or difficult to follow.