their timely and exciting contributions. We hope you ?nd this volume as useful as past volumes, which promises to be just as diverse with regard to ?uorescence-based content. Finally, in closing, I would like to thank Caroleann Aitken for helping coordin- ing content with authors and Michael Weston at Springer for help in publishing this current volume. Baltimore, MD, USA Chris D. Geddes v . Contents Fluorescence Anisotropy to Study the Preferential Orientation of Fluorophores in Ordered Bi-Dimensional Systems: Rhodamine 6G/Laponite Layered Films .................. 1 F. López Arbeloa, V. Martínez, T. Arbeloa, and I. López Arbeloa Room Temperature Tryptophan Phosphorescence of Proteins in the Composition of Biological Membranes and Solutions ....... 37 Vladimir M. Mazhul¿, Alexander V. Timoshenko, Ekaterina M.