Classical field theory predicts how physical fields interact with matter and is a logical precursor to quantum field theory. This introduction focuses purely on modern classical field theory, helping graduates and researchers understand classical field theory methods before embarking on future studies in quantum field theory. It describes various classical methods for fields with negligible quantum effects, for instance, electromagnetism and gravitational fields. It focuses on solutions that take advantage of classical field theory methods instead of applications or geometric properties. Other fields covered include fermionic fields, scalar fields and Chern-Simons fields. Methods such as symmetries, global and local methods, Noether theorem and energy-momentum tensor are also discussed, and important solutions of the classical equations, in particular soliton solutions.