Abstract: A door lock, requiring no penetration of a door leaf for unlocking from the outside, comprises a keeper secured to the inner surface of the door leaf, a housing slidably articulated to the keeper by two pivot studs, and a detent on an adjoining door post engageable by a pair of spring-loaded levers in the housing whose fulcra are a pair of pins normally immobilized by a retaining disk. With the door closed and the detent engaged, the housing fits around the keeper and can move away from it to a limited extent, allowing the door to be opened slightly, unless a handle on the housing is turned into a latching position engaging a bolt fixed to the keeper. Unlatching of the door from within, by reverse rotation of the handle, also disengages the levers from the detent so that the door can be opened wide. When the door is opened from the outside, its leaf is held ajar by the housing whose handle cannot be rotated in this position since the levers are blocked by the pivot studs.