Knight - Bond is on the right track, but didn't quite get the details correct. You can demolish your Library, but you will have to have 12 available (unused) research points before you will be allowed to queue the demolition. If you don't have enough free research points, you will have to 'Reset' one (or some) of the Researches you have done; thus freeing up the points that were originally used on the research. You get to choose which Researches get reset. You may have to reset more than one to get enough points to queue the demo. Each Research you reset will cost you one Culture Point.