[KyleGoetz]

Warning: books only written in kana are, in my opinion, harder to read for non-native beginners than books with kanji.

My first semester learning Japanese I could more easily read Blackjack (an adult-level manga) than Doraemon (a kid-level manga). This is because with kanji you have at least some hint of which words are being used and the divisions between words.

With only kana, you're not going to know where one "word" ends and another begins.

Note that if you're not a beginner, what I've said doesn't hold true. But if you can't read kanji, I'd say you're probably a beginner.