Question about 除了

 In my head I have a sentence remembered from an Elementary lesson that goes like this.

除了读书什么都不知道

 Meaning "apart from Studying what does he know?"

 I've struggled to understand how this sentence  gets that meaning  I think part of it maybe because of the omitted 以外 which I think would be here. -- 

除了读书以外什么都不知道

 Would it be right to brake it down to the following literal translation?

 Apart from books everything all not know.