My long-term research goal has been to understand how the vertebrate hypothalamus is built. This evolutionarily-ancient part of the brain centrally regulates homeostasis and adaptative mechanisms and is essential to life. Until recently, we and others have assumed that distinct progenitor cells in the hypothalamus are patterned in response to Sonic hedgehog acting as a spatial morphogen. Our recent work suggests a fundamentally different mechanism, in which the hypothalamus is built from a multipotent Fgf10+ stem-like progenitor that generates other hypothalamic progenitors and neurons in a predictable manner in space-and-time, and is itself retained - potentially even into adulthood. Shh acts locally to initiate progression of the Fgf10+ stem-like progenitor to a more-differentiated progenitor, and is part of a network that ensures the correct balance of stem-like and progenitor cells.