The chapter discusses the application of effective field theory (EFT) to the nuclear forces, focusing on the foundations and applications in few-nucleon systems. It begins by reviewing the chiral symmetry in Quantum Chromodynamics (QCD) and its spontaneous breaking, which leads to the formation of quark condensate and the appearance of Goldstone bosons, such as pions. The chapter then discusses the scales relevant to nuclear physics, including the Compton wavelength of the pion, the binding momentum, and the Fermi momentum in nuclear matter. It highlights the challenges in describing nuclear forces due to the large scattering lengths and the need for non-perturbative resummation in EFT. The chapter also covers conventional approaches to the nuclear force problem, such as meson field theory and dispersion relations, and their limitations. It introduces the concept of EFT, emphasizing its systematic and model-independent approach to calculating low-energy physics by exploiting the separation of scales. The pionless EFT, which integrates out the pions, is discussed in detail, along with its applications to electroweak processes and deuteron electrodisintegration. Finally, the chapter touches on the extension of EFT to many-body systems, including the construction of nuclear potentials from lattice QCD simulations and the study of hyperon-nucleon interactions. It concludes with a discussion on the observability of off-shell physics in nuclear phenomena and the implications for the interpretation of experimental data.The chapter discusses the application of effective field theory (EFT) to the nuclear forces, focusing on the foundations and applications in few-nucleon systems. It begins by reviewing the chiral symmetry in Quantum Chromodynamics (QCD) and its spontaneous breaking, which leads to the formation of quark condensate and the appearance of Goldstone bosons, such as pions. The chapter then discusses the scales relevant to nuclear physics, including the Compton wavelength of the pion, the binding momentum, and the Fermi momentum in nuclear matter. It highlights the challenges in describing nuclear forces due to the large scattering lengths and the need for non-perturbative resummation in EFT. The chapter also covers conventional approaches to the nuclear force problem, such as meson field theory and dispersion relations, and their limitations. It introduces the concept of EFT, emphasizing its systematic and model-independent approach to calculating low-energy physics by exploiting the separation of scales. The pionless EFT, which integrates out the pions, is discussed in detail, along with its applications to electroweak processes and deuteron electrodisintegration. Finally, the chapter touches on the extension of EFT to many-body systems, including the construction of nuclear potentials from lattice QCD simulations and the study of hyperon-nucleon interactions. It concludes with a discussion on the observability of off-shell physics in nuclear phenomena and the implications for the interpretation of experimental data.