Abstract

I discuss the current state of knowledge of PDFs, concentrating on the MSTW set. I particularly emphasize the sources of uncertainty, experimental, procedural and theoretical, and show how these can lead to differences between different PDF sets. The predictions for processes measured at the LHC and the possible tests these can provide on PDFs are illustrated. The predictions for the Higgs cross section at both the Tevatron and the LHC are summarised and the correlation with other LHC processes introduced.