This strategy guide WAS popular, & sold well. It is made by the competing strategy guide company Prima. It was also used in promotions by game stores to add to purchases of Sonic Adventure 1, even though it wasn't billed as 'official strategy guide' (notice how it says Prima's official guide...not 'the official guide'). It's a decent guide, with lots of photos, and of course, the stock art sprinkled throughout. This item is in the SonicGear collection.