He doesn't say so explicitly, but I'm guessing JD doesn't have a dog
in this fight per se, other than the book reviews he's offered :-).
That is, there is much to be said for using the Lagrangian to solve
problems, and not get too caught up in the philosophy of first
principles of "where it comes from or why it looks like it does."
Fair enough.
JD has offered this reference before and I agree that it is
interesting and useful. On looking at it again, unless I have missed
something, its *entire* relevance to *this* particular thread is a
lone statement in Section 1.6: "The key idea is to construct a
Lagrangian L such that Lagrange's equations are Newton's equations."