The study of cellular differentiation (and un-differentiation, as may be the case in cancer) is really taking off. I recommend the book "Epigenetic Revolution"

The study of cellular differentiation (and un-differentiation, as may be the case in cancer) is really taking off. I recommend the book "Epigenetic Revolution" by Nessa Carey to the laymen. It is the most accessible intro into the research that I know of.