Classical and Quantum Interference and Coherence.- Quantum Interference in Atomic Systems: Mathematical Formalism.- Superposition States and Modification of Spontaneous Emission Rates.- Quantum Interference as a Control of Decoherence.- Coherence Effects in Multi-Level Systems.- Field Induced Quantum Interference.- Slow and Fast Light and Storage of Photons.- Quantum Interference in Phase Space.- Quantum Interference in Atom Optics.