Over the last several decades, there has been an increasing interest in the measurement of radon and natural radioactivity throughout the world. One of the main reasons behind this is that both are health hazards and their measurement plays a critical role in monitoring of the human health. In this regard, an overview of radon is given wherein topics related to its origin, sources, dosimetry, etc. are described. Solid State Track Detectors are briefly discussed along with discovery of new etchants. From the measured radon and natural radioactivity levels in soil and building materials of the Bahawalpur Division of Pakistan, annual effective dose and excess lung cancer risk have been calculated. A mathematical model has been developed for radon exhalation rate. Determination of Uranium contents in ore samples using CR-39 based radon detectors has been discussed.