Recently significant advances have been achieved in precision calculations for the LHC. I will motivate
the necessity of NNLO precision to fully exploit the increasing accuracy of the data. The state of the art methods
used in such fixed order calculations are subtractions. I will try to give you an overview using NLO calculations as
a starting point. While NLO is generically solved, there are various different NNLO schemes on the market, each
having its advantages and disadvantages.
