They are good books. (I started the first one when writing a compiler). The valid criticisms of them relate to improvements in parsing, and in optimization, wh

They are good books. (I started the first one when writing a compiler). The valid criticisms of them relate to improvements in parsing, and in optimization, which has progressed significantly in the years that they were written. Fun fact: On the compiler we wrote, Jeanne Musinski PhD, a student of Ullman was on our team. She wrote the parser, and actually discovered an improvement in error recovery during our project and published a paper after conferring with Ullman.