1. What are Microclusters? -- 1.1 Constituent Small Particles of Material -- 1.2 Division of the Materials -- 1.3 Shell Periodicity of Atomic Structure -- 2. Dynamics of Atomic Structure -- 2.1 Solid-like, Liquid-like, or Fluctuating? -- 2.2 Coexistence of Solid-like and Liquid-like Phases -- 2.3 Fluctuating States and Permutation Isomers -- 2.4 Monte-Carlo Simulations -- 2.5 Spontaneous Alloying -- 3. Shell Structure of Metal Clusters -- 3.1 Magic Numbers -- 3.2 The Jellium Model -- 3.3 Theory of Shell Correction -- 3.4 Deformation -- 3.5 Fission -- 3.6 Shell Structure in Large Metal Clusters -- 4. Other Properties of Metal Clusters -- 4.1 Non-Empirical Calculation of Alkali-Metal Clusters -- 4.2 Electronic Structure of Noble-Metal Clusters -- 4.3 Magnetic Properties of Transition-Metal Clusters -- 4.4 Oscillatory Magnetic Moments of Nickel Clusters -- 4.5 Divalent-Metal Clusters -- 4.6 Trivalent-Metal Clusters, AlN -- 5. Semiconductor Clusters -- 5.1 Carbon Clusters -- 5.2 Stabilities of Silicon and Germanium Clusters -- 5.3 Nonempirical Calculations for Si6 and Si10 -- 5.4 Force and Vidal Analysis of Larger Silicon Clusters -- 5.5 Recent Nonempirical Calculations for Large Silicon Clusters -- 6. Rare-Gas Clusters -- 6.1 The Magic Numbers for Packing -- 6.2 Helium Clusters -- 7. Molecular Clusters -- 7.1 Photoionization of Ammonia Clusters -- 7.2 Ion-Centered Cage Structure -- 7.3 Water Clusters -- 7.4 Negatively Charged Water Clusters -- 7.5 Electron Attachment to van der Waals Clusters -- 8. Chemical Bonds and Related Topics -- 8.1 Effects of Electron Correlation, and the Optimization of Geometry on Magnetism -- 8.2 Synthetic Chemistry in a Cluster Beam -- 8.3 Generation of a Latent Image -- 8.4 Van der Waals and Metallic Mercury Clusters -- 8.5 Scattering of Microclusters -- References.