Quantum field theories emerged from the confluence of quantum mechanics and special relativity, and provide an amazingly accurate theoretical framework for describing the behaviour of subatomic particles and forces. This course will give an introduction into quantum field theory, both conceptually and technically. Canonical and covariant quantization methods will be discussed, with an emphasis on the path integral formulation, which finds manifold applications in both particle physics and condensed matter systems. Topics covered include the quantum-mechanical path integral, the quantization of bosonic and fermionic fields, functional techniques involving generating functionals and correlators, and perturbation theory in terms of Feynman diagrams.