The idea of anti-ferromagnetic order was initially greeted with skeptism when Louis Neel introduced it in the ‘30s but is now considered obvious. Indeed the search for an exception has turned up empty-handed for 30 years until recently, when a couple of promising examples have surfaced. I shall argue that if confirmed, this represent a new state of matter, called quantum spin liquid, which exhibits novel properties such as emergent fermionic excitations and gauge fields and is related to the de-confinement of a strongly coupled lattice gauge theory