You can do this in Muler, too... and I mention that only because the way a Muler table is structured allows for math to be done to your roll before you access the table return. For instance, if your spells ramped up in power/efficacy as you got closer to 990, then there could be a mod that might give you a boost: 1d990 + 100 Which would effectively cut off the bottom 100 (less powerful) spells. Another option would be if the GM said, "You book blows open in the wind and stops on page 654. What is that spell?" That is when you need to be able to return that particular entry rather than rolling randomly. Muler can give you that kind of static-access, where a rollable table cannot. So if the math of the roll might matter, or if the likelihood of a given entry might change (instead of everything weighted as 1, some are worth more), or if you might have to designate what item you are returning, then you might want to think about Muler. If your odds would never change, and you will alwyas open the spell book randomly, then you could easily handle this with a rollable table.