Japanese Verbs at a Glance - Naoko Chino (Power Japanese Series)

The page layout is rather pedestrian and crowded, but it's as comprehensive as anything I've seen and offers very clear breakdown and analysis of the various verb forms. Extremely useful for both beginners and intermediates. Highly recomended.
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All About Particles - Naoko Chino (Power Japanese Series)

Another good Power Japanese book, again very comprehensive. Covers all the various meanings and usages of every particle you've ever heard of (and more). Numerous clear example sentences. Recommended.
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Outrageous Japanese : Slang, Curses & Epithets - Jack Seward

You'd be forgiven for thinking that there were no swearwords in Japanese... time to set the myth straight. The slang section is also pretty impressive. It's not exactly essential for most students of the language, but is bound to come in handy if, like me, your Japanese is mainly employed during drunken conversations in seedy Tokyo bars.
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