Similarly Dunn & Wakefield Exposure manual. The concepts stand well but modern meters are better at their jobs.
In both cases it is prudent to modify some specifics to adapt to the new world when it makes sense.
For me "finally" finding out what normal was and getting good at normal allowed me to get much better at everything, it gave me a baseline where things worked well and a way to judge what changes improved things and which didn't.
I have tested to find the limits of "normal", the range I can shoot in to get a good print, but my intent isn't to find a personal EI, it is to figure out where to stop when I have to move away from normal/box speed.