Title: Chiral Fermions in Condensed Matter Physics  Abstract: Chirality, or handedness, is a geometrical property given to a figure if its mirror image cannot be brought to coincide with itself. The concept of chirality plays a role in biology, chemistry, and physics from the homochirality of the molecular basis of life to the new states of matter produced in heavy-ion collisions. After a quick review, I will present the case studies involving chiral fermions in condensed matters, such as Dirac and Weyl semimetals. The chiral anomaly sourced by parallel electric and magnetic fields produces an imbalance between the densities of right- and left-handed fermions, leading to the generation of electric current. This is the chiral magnetic effect first observed in Dirac semimetal ZrTe5. Coupling of circular polarized light to chiral fermions breaks the chiral symmetry, leading to the generation of chirality-dependent photocurrent and THz emission that may be used for quantum information systems. Finally, I will briefly discuss topological phase transitions involving chiral materials.