The book is composed of detailed principles, methods and findings of genetic engineering of colour variants of Aequorea victoria green fluorescent protein (GFP) for thermo-stability, refolding kinetics and pH-sensitivity. In addition, principles and methods to engineer the GFP to develop its destabilized version with a potential to study transient expression of cytoplasmic proteins are meticulously presented. The GFP was also used as a model substrate to elucidate the possible chaperone activity of bacterial initiation factor IF2. Of particular interest is the developed methodology, used throughout the study, to read the fluorescence of the protein in real time using RT-PCR machine while treating the sample at temperature of interest (25-99°C) for the intended period. Such method has never been developed and used before. Much more detailed, handy and innovative methodologies are addressed in the text. Thus, the book, which was forwarded by Prof. Chemeda Fininsa, is intended for graduate students, academicians, beginner and advanced researchers in the area of genetic engineering and biotechnology.