This book presents the basic and advanced research topics under the broad domain of nuclear instrumentation and control. It also covers various novel approaches that are adopted by the designers of nuclear systems for improved efficiency and safety, which demands state-of-the-art control and instrumentation techniques and technology. Various topics covered in this book are radiation monitoring systems, reactor instrumentation, neutron detectors,  instrumentation for sodium cooled fast reactors, core monitoring aspects in thermal reactor systems, developments in gamma detectors leading to sophisticated characterization tools in materials science and medical diagnosis among many others. The book will be useful for the researchers and professionals in the allied fields.