Preface to the special issue.

I also thank the contributors, each a luminary in the field, who participated in interviews about the past and future of GnRH research for the article ending this Special Issue. Guillemin and Schally for the discovery that led to the wide array of research covered in this Special Issue, and hope that they enjoy reading it as the latest fruition of their work. It was 50 years ago last summer that Roger Guillemin and Andrew Schally published their breakthrough papers reporting the isolation and discovery of the peptide sequence of gonadotropin-releasing hormone (GnRH), for which they were later awarded the Nobel Prize. [Extracted from the article]