Although transcriptional regulation in bacteria is well understood in general, only few transcriptional regulators have been studied in detail. In this book, several important steps in the characterisation of the transcription factor CcpN from Bacillus subtilis are explained. This includes detailed information about the experimental procedures necessary to investigate transcriptional regulators with rather simple, yet very yielding means. CcpN is a transcription factor that has been first characterised in 2005. It plays an important role in carbon catabolite repression in the Gram-positive bacterium Bacillus subtilis.