Jay Rubin, Professor of Japanese Literature at Harvard, has put together a nifty tome which explains a whole swag of Japanese grammaticisms in a way which makes the reader stop, think for a moment and say "Now I get it!". Rubin explains by means of anecdote and analogy exactly how troublesome aspects of the Japanese language actually work, and by the end of the book concepts like wa/ga, kureru/kudasaru, kimeru/kimaru no longer seem arcane and incomprehensible. I think the book is worth the price simply for the excellent explanation of how kureru/kudasaru/itadaku/ageru work on the basis of what direction the action occurs. Until I read MSOJ this concept confused me, and heeding the words of my original Japanese teacher I was loathe to even use the ageru construction lest I imply that I was doing a person a favour and thereby burdening them with obligation, but Rubin's lucid explanation left me excited that I could finally use the Japanese words for give. Not so useful for a beginner - MSOJ is perfect for someone who has studied Japanese for a while and needs a bit of a meta-cognitive boost.