  This Report summarizes the proceedings of the 2019 Les Houches workshop on
Physics at TeV Colliders. Session 1 dealt with (I) new developments for high
precision Standard Model calculations, (II) the sensitivity of parton
distribution functions to the experimental inputs, (III) new developments in
jet substructure techniques and a detailed examination of gluon fragmentation
at the LHC, (IV) issues in the theoretical description of the production of
Standard Model Higgs bosons and how to relate experimental measurements, and
(V) Monte Carlo event generator studies relating to PDF evolution and
comparisons of important processes at the LHC.
