Introduction.- Unitarity of Gravity Coupled to Models of Particle Physics.- Unitarity of Models with Extra Dimensions.- Higgs Inflation.- Bound on the Non-minimal Coupling of the Higgs Boson to Gravity.- Conclusions.- Appendix A Polarisations of External Particles.- Appendix B Wigner d-Functions.- Appendix C Integrals.- Appendix D Transforming Between Einstein and Jordan Frames.- Appendix E Feynman Rules.