What can I say about "Decoction!" that hasn't already been said? Pretty much anything as no-one has ever said bugger all about it.
Mini Book Series volume IV, "Decoction!" is a celebration of central European beer. It covers tricky and poorly documented topics such as Lager styles, methods of decoction mashing, extinct German top-fermenting styles and more detail on Berliner Weisse in English than anywhere else.
It's a handy companion to the Oxford Companion to Beer, for those worried about little details such as accuracy and completeness. A full set of my books is certainly a more reliable reference than the OCB, if a tad more expensive. But at least the money goes to poor starving children (Andrew and Lexie) rather than the rapacious OUP.