In particle physics a hadron is a composite particle made of quarks held together by the strong force (in a similar way as molecules are held together by the electromagnetic force). Hadrons are categorized into two families: 1) baryons, made of three quarks; and 2) mesons, made of one quark and one antiquark. Protons and neutrons are examples of baryons and pions are an example of a meson. Hadrons containing more than three valence quarks (exotic hadrons) have been discovered in recent years. A tetraquark state (an exotic meson), named the Z(4430), was discovered in 2007 by the Belle Collaboration and con rmed as a resonance in 2014 by the LHCb collaboration. Two pentaquark states (exotic baryons), named P+c (4380) and P+c (4450), were discovered in 2015 by the LHCb collaboration. There are several more exotic hadron candidates, and other colour-singlet quark combinations may also exist. Of the hadrons, protons are stable, and neutrons bound within atomic nuclei are stable. Other hadrons are unstable under ordinary conditions and free neutrons decay with a half-life of about 611seconds. Experimentally, hadron physics is studied by colliding protons ornuclei of heavy elements such as lead, and detecting the debris produced in the resulting particle showers. This book gives an concise overview of Hadronic Matter."