Lectures -- Investigating Physical Systems with Optical Spectroscopy -- Light-Matter Interactions on the Femtosecond Time Scale -- Photons and Photon Statistics: From Incandescent Light to Lasers -- Carrier-Wave Nonlinear Optics -- Carotenoid Excited States-Photophysics, Ultrafast Dynamics and Photosynthetic Functions -- Spectroscopy of Quantum Wells and Superlattices -- Lasers for Frontier Spectroscopy -- Coherent Spectroscopy of Stratified Semiconductor Micro- and Nanostructures -- Consequences of Extreme Photon Confinement in Micro- Cavities: I. Ultra-Sensitive Dedection of Perturbations by Bio-Molecules -- Luminescence Properties of Very Small Semiconductor Particles -- An Introduction to the Physics of Ultracold Atomic Gases -- Laser Cooling and Trapping of Neutral Atoms to Ultralow Temperatures -- Ultrafast Structural Dynamics in the Condensed Phase -- Lanthanide Series Spectroscopy Under Extreme Condition -- Excitonic Bose-Einstein Condensation versus Electron-Hole Plasma Formation -- Dynamics of Solid-State Coherent Light Sources -- Some Novel Aspects of Intramolecular Electronic Energy Transfer Processes -- Stimulated Raman Scattering Spectroscopy of Frontier Nonlinear-Laser Materials: Organic Crystals and Nanocrystalline Ceramics -- Interdisciplinary Lecture -- Strange Properties of Quantum Systems and Possible Interpretations -- Long Seminars -- Modulation Spectroscopy Revisited -- Advances in Solid State Lasers at NASA Langley Research Center -- Combinatorial Chemistry to Grow Single Crystals and Analysis of Concentration Quenching Processes: Application To Yb3+-Doped Laser Crystals -- Table-Top Soft X-Ray Lasers and Their Applications -- Rare Earth Ion Doped Ceramic Laser Materials -- Short Seminars -- Posters.Advanced spectroscopic techniques allow the probing of very small systems and very fast phenomena, conditions that can be considered "extreme" at the present status of our experimentation and knowledge. Quantum dots, nanocrystals and single molecules are examples of the former and events on the femtosecond scale examples of the latter. The purpose of this book is to examine the realm of phenomena of such extreme type and the techniques that permit their investigations. Each author has developed a coherent section of the program starting at a somewhat fundamental level and ultimately reaching the frontier of knowledge in the field in a systematic and didactic fashion. The formal lectures are complemented by additional seminars.