Whatever, you read today will be outdated in 10 years. I would find something that works for you and stick with it. I still think Arthur Lydiard had it right. Daniel's is decent. I don't know pfitz. I also really liked Steve Magness' book Science of Running especially later chapters. The first chapters were heavier Science and I had to read them several times to get them.
Pfitz is basically Lydiard. He was even on the board of the Lydiard Foundation at one stage (and possibily still is).
I saw somewhere that Squires based a lot of his approach on Lydiard principles. From my experience of both there is certainly a large overlap in approaches, but I think Squires' surge long runs prepare you better for racing a marathon than Lydiard's approach did.
IMO Lydiard is fantastic for 10km down, but doesn't quite get it right over the marathon (something he acknowledged himself).
@HRE - thanks for the link. Good to know it's still around.
I didn't know that about Lydiard and the marathon. Possibly because I am a middle distance runner.
Just take Daniels hardest plan and add a coctail of supplements and PEDs, then add a few extra workouts that would not be possible without them. Presto! Modern traing plans.