I couldn't help but throw these guys just to make you guys jelous...
There's a small handbook that talks about Soh Brothers' marathon coaching phylosophy...
Most recent one from Japan is from equivalent of Japanese T&FN; it's a booklet of interviews of and stories written by many of Japanese best marathon runners; Toshihiko Seko, Soh Brothers, Naoko Takahashi, Yuko Arimori, Takeyuki Nakayama, Hiromi Taniguchi...going way back with Akio Usami, Kenji Kimihara, etc. This is absolutely a priceless piece. I showed that to Nick Bideau and he was drewling over it. These guys are talking about marathon training secret, training attitude, running form, extra exercises, etc. This is one-step-more-in-depth "How They Train". There soon will be a training secret of Seko coming up this spring.
There are two books written by the late Kiyoshi Nakamura which are also priceless: one is called "Marathon is My Life" and the other one (the better one) called "Find, Develop, (make them) Live". The latter much more than just a training manual (kind of like "How to Become a Champion").
Tons of books on Naoko Takahashi and by Yoshio Koide. Particularly there's one by Koide that led me to suggest Arthur Lydiard to pick Takahashi as the gold medalist at Sydney Olympic marathon--talk about paying attention to details!
Sorry, guys. None of these have been translated in English!