Gauge field theory -- DIAGRAMMAR / G't. Hooft and M. Veltman -- Gauge theories with unified weak, electromagnetic and strong interactions -- The Renormalization Group in Quantum Field Theory -- Extended objects in gauge field theories -- Magnetic monopoles in unified gauge theories -- Computation of the quantum effects due to a four-dimensional pseudoparticle -- How instantons solve the U(1) problem -- Naturalness, chiral symmetry, and spontaneous chiral symmetry breaking -- Planar diagram field theories -- A two-dimensional model for mesons -- Epilogue to the Two-Dimensional Model -- Confinement and topology in non-Abelian gauge theories -- The confinement phenomenon in quantum field theory -- Can we make sense out of "Quantum Chromodynamics"? -- Quantum gravity -- Classical N-particle cosmology in 2 + 1 dimensions -- On the quantum structure of a black hole -- The gravitational shock wave of a massless particle / G't. Hooft and T. Dray -- S-matrix theory for black holes.