Agreed with Nashiro. Those guides can be better than the official paid ones. I bow down to them for dissecting and presenting the games' quickest paths, simplest solutions, and in-depth mechanics so wonderfully.
I bought a magazine copy of a fully-comprehensive walkthrough for Super Smash Bros Brawl shortly after getting that. Normally I like to find and figure everything out on my own, but knowing the Smash Bros games were generally difficult to finish and earn everything - I knew that book would come in handy, and it totally did. Worth every penny