Carbon Stars and Nucleosynthesis in Galaxies
  The role of carbon stars in the build-up of chemical elements in galaxies is discussed on the basis of stellar evolution calculations and estimated stellar yields, abundance analyses of AGB stars, galactic-evolution models and abundance trends among solar-type disk stars. We conclude that the AGB stars in general, and carbon stars in particular, probably are main contributors of $s$-elements, that their contributions of flourine and carbon are quite significant, and that possibly their contributions of lithium, $^{13}$C and $^{22}$Ne are of some importance. Also contributions of N, Na and Al are discussed. The major uncertainties that characterize almost any statement concerning these issues are underlined. 
Bengt Gustafsson and Nils Ryde