William Goldman's sequel to Adventures in the Screen Trade, Which Lie Did I Tell? was a really interesting book and an enjoyable read, more so than the first one. There are two main reasons for this.
The first is that being 26, I hadn't seen many of the movies discussed in the first book, and so the references were more abstract. This effect will obviously vary with the age of the reader, but I suspect that the audience for people considering a career in the screen trade is not that old, simply because few people take up new careers in their 40s and 50s (I find it very reassuring that some people do, and many of the ones who do do so quite successfully).
The other, more significant reason, is that Goldman matured. When he wrote Adventures, he was 52, whereas Which Lie was written when Goldman was 69. It's generally been my experience that people in their sixties tend to be either a lot more crotchety, or a lot more mellow, than themselves in their 40s and 50s. Part of it may be simply getting tired, but I think much more it's that after 40 years of working and worrying, people have seen enough of the world to realize that they don't need to worry nearly as much as they thought that they did when they were younger. Whatever the reason, Goldman does seem much more at peace with hollywood when he started. (I don't mean to give the impression that he praises it; he still observes many of the idiocies and ego-driven problems which go on in hollywood, but he has more of a sense of humor about it.)
In any event, I recommend Which Lie Did I Tell? even more strongly than I did Adventures in the Screen Trade. It's a great complement to the first book — I bought them at the same time and read them together, and I think that I did the right thing. The second doesn't require the first to have been read, but I think that you get more out of them together.