Preface. 1. Mesocrystals and Nonclassical Crystallization. 2. Physico-Chemical Principles of Crystallization. 3. Examples of Crystals Challenging the Classical Textbook Mechanism. 4. Nonclassical Crystallization. 5. Self-Assembly and Self-Organization. 6. Colloidal Crystals with Spherical Units: Opals and Colloidal Nanocrystals. 7. Mesocrystal Systems. 8. Mechanism of Mesocrystal Formation. 9. Analysis of Mesocrystals. 10. Tuning of Properties. 11. A Unifying Crystallization Mechanism. 12. Analogy between Oriented Attachment or Hierarchically Structured Crystals and Polymers. 13. Summary and Outlook. Index.