Spot on, Declan, I'm from the same mould! Also, as Rob said, it's also about a stab at what you think you can get for a coin because, hobbiest or business man, most of us are hoping to buy something else with the released funds! I actually like Spink's book because I physically can't remember everything about everything I see. However, Spink's takes it's prices from hopefully a lot of different sales, which will have included an infinite amount of coin faults. To clarify the complexity of value, I have a BU 1936 penny which I'm really pleased with and can't conceive of bettering, however, I also have a beautiful, luminous, burgundy-toned '36 which, I couldn't value less! Also, I have three different elizabeth I 3d's, which fall under the same spink number, but one is around 6 x rarer than the others, and would sell well above the spink price guide...that's what you're up against! Enjoy!