The discovery of haploid Datura plants in 1964 initiated great excitement in plant breeding and genetics communities. Recent years have witnessed a resurgence in activities especially in developing protocols, identifying genes and mechanisms and large scale commercial take up.The identification of controlling genes has driven functional genomic studies which now link in with studies in gene expression, metabolism and changes in cell ultra-structure. World wide take up by plant breeders has been no less impressive and valuable haploid technologies is increasingly patent protected. The intense activity in haploid research has also resulted in unexpected findings with novel applications.The core of this book is based on the international symposium on 'Haploidy in Higher Plants III', (Vienna 2006), which attracted top international experts in the field. Other invited contributions have been included to provide a rounded view of activities.