Elements of quantum electrodynamics -- Quantum states of bosonic systems -- Bosonic systems in phase space -- Quantum theory of damping -- Photoelectric detection of light -- Quantum-state reconstruction -- Nonclassicality and entanglement of bosonic systems -- Leaky optical cavities -- Medium-assisted electromagnetic vacuum effects -- Resonance fluorescence -- A single atom in a high-Q cavity -- Laser-driven quantized motion of a trapped atom.