[en] This text contains the following subjects. (1) Introduction, (2) Beam dynamics in longitudinal direction, (2-1) Transition energy, (2-2) The principle of phase stability, (2-3) Synchrotron oscillation with a small amplitude, (2-4) Synchrotron oscillation with a large amplitude, (3) Beam dynamics in transverse direction, (3-1) The principle of strong focusing, (3-2) Betatron oscillation, (3-3) Courant-Snyder invariant, (3-4) Dispersion, (3-5) Chromaticity, (4) Synchrotron radiation, (4-1) Radiation damping of synchrotron oscillation, (4-2) Radiation damping of vertical betatron oscillation, (4-3) Radiation damping of horizontal betatron oscillation, (4-4) Damping/Partition number, (4-5) Radiation excitation of synchrotron oscillation, (4-6) Radiation excitation of betatron oscillation, (5) Radiation integral, (6) For realization of low emittance, (6-1) FODO, (6-2) Double Bend Achromat (DBA), (6-3) Theoretical Minimum Emittance (TME), (7) Damping ring of International Linear Collider (ILC), (7-1) Outline, (7-2) Requirements for damping ring, (7-3) Design of damping ring, (7-4) Dynamic aperture, (7-5) Other issues to be investigated. (K.Y.)