"It's almost as if....someone pulled all his works and references from the libraries."
Diakoptics is still available on Amazon, as well as a book from L.V. Bewley 'Tensor Analysis of Electric Circuits and Machines'. He says in the introduction that it was a gathering together in one text all of the work on the subject that Kron had done up to the early 60's (I have Bewley's book that used to sit on a shelf at the U.S. Navy Postgraduate school in Monterey CA--Based on the cards at the back of the book, it was last checked out of the library in 1987, which explains why it was up for sale).