Dwarf galaxies in the Local Group allow to study in great detail the physical mechanisms responsible for the formation and evolution of galaxies. In fact, their resolved stellar populations allow to unveil their star formation and chemical evolution histories back to the earliest epochs. In particular, they can be used to constrain the efficiency of both local (Supernovae, SN) and global (reionization) mechanisms. The most isolated galaxies are the particularly interesting because, not having suffered strong interactions with the giant galaxies, they are free from environmental effects and they are ideal probes to test the early evolution of dwarf systems. I summarize here some of the latest results concerning isolated galaxies in the Local Group, with particular enphasis on the result of the LCID project.