An Introduction to Anion Receptors Based on Organic Frameworks -- Metal-Based Anion Receptor Systems -- Recent Progress of Phosphate Derivatives Recognition Utilizing Artificial Small Molecular Receptors in Aqueous Media -- Anions and?-Aromatic Systems. Do They Interact Attractively? -- Anion Templates in Synthesis and Dynamic Combinatorial Libraries -- Molecularly Imprinted Polymers Using Anions as Templates