Some selected comments on cosmic radioactivities

Radionuclides with half-lives ranging from some years to billions of years presumably synthesized outside of the solar system are now recorded in live' or fossil’ form in various types of materials, like meteorites or the galactic cosmic rays. They bring specific astrophysical messages the deciphering of which is briefly reviewed here, with special emphasis on the contribution of Jerry Wasserburg and his collaborators to this exciting field of research. A brief mention is also made to $\gamma$-ray line astrophysics. It provides an interesting information on live short-lived radionuclides in the present interstellar medium, and thus complements in a very important way the study of extinct radionuclides in meteorites.