It's generally never worth the money to buy any type of video game guide. 20 years ago, when the video game industry was still young and the internet was a mere experiment, paying for video game guides was pretty popular. These days, with the internet being so prevalent and everything, you can find free guides (note: I don't mean illegal copies) almost everywhere.
And it just dawned on me that you're likely here to advertise the guide. Blergh.