I am not sure anyone would think you could learn how to write a compiler from scratch from Muchnick's book. It is a fantastic book, easily one of the best CS books I have ever read. However, the author makes it pretty clear from the get go that it isn't a book to learn to write a compiler. You should already know how to do that. It is a book to learn to write a really good production optimizing compiler. He expects a lot from his readers, and if you don't have the background you will quickly give up (as I did the first time I tried to read it).
I learned to write a compiler from the Dragon Book. I taught myself how to do it. It took me several years to become good at it. However, I consider that experience invaluable. While, the original article advocated just diving in to the compiler without a lot of background on lexing and parsing. I personally wasn't happy until I had written my own parser generator and fast regex engine (which I learn how to do from Russ Cox's excellent articles on the subject).
I learned to write a compiler from the Dragon Book. I taught myself how to do it. It took me several years to become good at it. However, I consider that experience invaluable. While, the original article advocated just diving in to the compiler without a lot of background on lexing and parsing. I personally wasn't happy until I had written my own parser generator and fast regex engine (which I learn how to do from Russ Cox's excellent articles on the subject).