A lead research reactor of a small thermal power, of the order of 20-25 MW, can be built in future, and will provide the necessary medical radioisotopes and, at the same time, accumulate experience with metal fuel and heavy lead coolant. Perhaps this goal was set by the author when writing this book. The book describes the design of a hard lead reactor with a capacity of 25 MW, and based on the calculated hard neutron flux densities, estimates of those activities are given, in Curie units, that can be expected when irradiating light targets, Z 40, in the core of such a hypothetical reactor.