Published in 1981, I bought this when I saw it mentioned in an article on compilers, and someone mentioned this as being a model of what a book about a computer language should be.
It’s interesting to see the way in which this book works, and it’s probably a good model for low-level programming. A fascinating insight into a little-used language these days, and still quite readable even if you can’t get your head round BCPL. Modern programmers new to antique languages will find it strangely fascinating: no strings, no classes, no memory management. It’s about as low level as you can get, and yet there’s concepts in there (write once, run anywhere) that are bang up to date in the latest languages.
A fascinating read for anyone seriously interesting in the history of computing.
/edit: I originally had the name as “BCPL: The Compiler and its Construction”. Doh.