This significant new publication on genomic or parental imprinting has been prepared by an outstanding team of international authorities. Genomic imprinting results in the preferential expression of one allele, depending on the parent of origin. It is associated with several disease syndromes in humans. Interest in this area has expanded rapidly from the time when it was first recognised that some important hereditary characterisitics were not adequately explained by the Mendelian laws of inheritance. The chapters cover a wealth of material to help explain not only the mechanisms of genomic imprinting but its biological and medical consequences.