Book & CD. Advances in molecular biotechnology have greatly improved the sensitivity and the efficiency of methods utilised for genetic investigations and diagnosis. In the domain of chromosome analysis, the introduction of molecular techniques has led to the development of a new approach, called Molecular Cytogenetics, which has surpassed previously available techniques to become a foremost biological method. The fluorescence in situ hybridisation (FISH) is quickly became the standard technique for in situ chromosomal investigations, as illustrated by its large variety of applications in research and diagnosis. However, during the last decade, alternative methods to FISH have been introduced and have shown to be valuable in detecting chromosomes and quantifying chromosomal abnormalities. These alternative procedures are the Primed IN Situ (PRINS) labelling and the Peptide Nucleic Acid (PNA) probes. The two procedures present several advantages for the in situ detection of nucleic acid sequences, such as the small size of PNA probes and PRINS primers, or the fast kinetics of PRINS and PNA labelling reactions, that make them very attractive for a number of cytogenetic purposes. This book provides a valuable introduction and overview of the principles and the applications of alternative approaches in the field of molecular cytogenetics.