I first met Roger in 1975, just as TPIR was going to one hour, and worked with him for two years at G-T, so I feel I know him reasonably well.
Since then I've seen many interviews with him and if he is bitter, sorry, I just don't see it.
Kathleen Bradley is a relative latecomer to the show. I don't need to read any more about Barker and the models, thus I won't be buying her book.
The documentary doesn't mention that Barker didn't get an Emmy in 1980 because TPTB submitted his entry after the 1980 deadline for submissions. That had to make Barker a little bitter. He loves to gloat about his Emmy's.