The volume Radiological Protection is not only a compilation of numerical data and functional relationships for practical purposes. Rather a comprehensive accompanying text is intended to impart to the scientific or professional user of Radiological Protection both data, the concepts and scientific bases of the discipline devoted to prevention of health risks to man from exposure to ionizing radiations and radionuclides. It contains contributions of experts internationally qualified in scientific disciplines or subjects such as radiation physics, biology and medicine, external and internal dosimetry of ionizing radiation and radionuclides, decontamination and decorporation of radionuclides, physical and biological measuring techniques, assessment of radiation shielding (restricted to an extent being necessary for completion of tasks of practical radiological protection, specifically in the field of lower energies). The CD-ROM delivered with the hardcopy of the volume contains the full text of the volume and in addition information and data, which would be beyond the scope of the printed version, within the interactive programme SISy (for MS-Windows only). These refer e.g. to decay data of radionuclides or normalized excretion functions for monitoring workers by quantitative assessment of intakes of radionuclides and calculation of resulting doses.