This book is a clearly laid out and well explained collection of idioms. The main part of the book devotes a page per expression to a wide variety of common Japanese idioms like とことんまで (to the bitter end) and しらぬ が ほとけ (ignorance is bliss). Each page contains a sample two line dialogue incorporating the idiom, an English translation of the dialogue, a paragraph explaining the idiom, its derivation and usage, and finally 5 example sentences using the idiom, with English translations.
The last part of the book contains a list of additional idioms, with English translations but without explanations or examples (bringing the total number to 600).
TCJEG is for intermediate to advanced learners – if you are looking to use expressions like 無駄足が運ぶ (go on a wild goose chase) I think you can count yourself as having progressed from the beginners pack. My personal take is that the book is better as a reference guide than as a source of phrases to throw around at your next party, because trying too hard to use an idiom you have just studied can make you sound unnatural, but if you take the time to read through TCJEG you will soon find that idioms hitting your ear every day will start making sense. You will soon realize that 顔が広い does not mean someone has a fat face but rather a big Rolodex.
If there is a downside it is the use of romaji – kanji/kana are only used to render each idiom at the top of the page – after that it is roman letters the whole way. [courtesy of Nihongojouzu.com]