RNA splicing is the process by which the non-coding regions of pre-messenger RNA are removed and mRNA takes its mature form which is subsequently translated to proteins. RNA splicing heavily relies on signalling mechanisms and, depending on the presence and availability of different signalling molecules, alternative splicing at different sites of the mRNA can occur. This leads to a variation in mRNA procucts derived from the same pre mRNA, and cosequently gives rise to protein products which might differ in sequence and function. Major advances in the detection methods of splicing variants during last decade have demonstrated that alternative splicing underlies many diseases such as Cystic Fibrosis, Fragile X syndrome and different types of cancer. This has not only enforced the need to further elucidate splicing mechanisms, but has also highlighted the need to study alternative splicing at a clinical level. The present book provides all the basic background information on splicing and aims to serve as a laboratory manual for all researchers and doctors who use methods to select splicing variants in the lab and in the clinic.