This is a good collection of papers dating from the 1970s and early 1980s. In some respects, the papers have aged well: they discuss concepts that are still important (and often ignored or re-invented) today. At other times however, they show their age: operating systems are still very basic and a lot of programming is still done in microcode for specific architectures, so they discuss things that are abstracted away in current computers.
I must admit that I did not read every paper, but only those that interested me, and I skim-read a few others. Those that talk only about graphical interfaces are not so interesting to the modern reader (especially when they must introduce the concept of a “mouse”).
Those papers that I most enjoyed however were the first paper, which sets down a number of elements that are important in an interactive editor, the UNIX paper and the EMACS paper. I also enjoyed the more high-level parts of the Lisp Machine paper.