I am not really sure about the audience and the purpose of the book... not true... I have got some suspicions and they don't go down that well with me...
The original edition (it was re-worked a little in the mid-eighties) was written for a British audience still suffering from food rationing (which continued until about 1954, the British won the war and lost the peace, and even unto this day any football game against Germany is billed as a re-enactment of World War 2) and from the lack of a national cuisine (no, baked beans is not the national British dish, just a watered-down version of Boston beans, and those are quite nice when properly done).
As one would expect, the book is addressed to those who know what they are doing in their kitchen and have all the time in the world ("roast the chicken in the usual way", all the vagaries found in Apicius, take such-and-such, it must be fresh and don't dare overcook the rice), but then someone who knows what he is doing wouldn't need the advice offered. (Except if they are British, of course, and have never tasted proper food.)
It must be literature, then, but it is very conscious of itself and its status as a classic, the references to ewe mutton are still there and are now references to "ewe mutton, should you ever have to deal with it", and that is that kind of self-conscious pretentiousness I just hate. The Guttuso illustrations are sadly missing, careless editing has seen to that, the references in the text are stil present as dangling pointers.