This book offers comprehensive coverage of most (not all) of the characters in everyday use, including the two syllabaries. Adequately thorough essays discuss the history of the Japanese writing system. However, in all honesty, no book can help you master the intricacies of kanji unless your brain is prebuilt for it. You see, kanji consist of hundreds of miniature pictographic elements that are combined and recombined. I refer not to radicals, but to tiny constituents thereof: for example, the compound kanji ('jukugo') for "magazine" is best viewed as 'nine tree chicken words scholar heart'. Now, if you can trivially surmount such extraordinary demands on your memory, you'll do fine, but if you can't, you won't. Remember: even though an American junior high-school student can read (albeit, obviously, not completely understand) a college-level textbook written in English, a Japanese college student is still learning how to read and write Japanese! Almost incredibly, too, the Japanese methodology for inculcating the kanji within the student is not to address the etymological or mini-pictological aspects of the character set, but, rather, drill, drill, drill, drill. No wonder the Japanese are such outstanding imitators but less than stellar initiators!

You might enjoy "Read Japanese Today" by Len Walsh.