What is the author's style in A Civil Action by Jonathan Harr?

Given the depth of Harr's immersion into the inner-workings of one side of a litigation, the perspective can be seen as third person omniscient. He is obviously able, with ease and credibility, to relate not just actions and events but also the inner thoughts of the major plaintiff figures, which, as he clearly points out in the end notes of the work, were expressed to him personally. After the trial, moreover, he conducted lengthy interviews with both Facher and Cheeseman, even attending Facher's class at Harvard and sharing dinner with him afterward. He has thus been able to give the reader a relatively clear picture of the personalities and litigation strengths/weaknesses of these individuals as well.