<p>An automatically locking crossbolt deadlock (2). Deadlock (2) includes a vertically movable crossbolt (36) which may be moved between locked and unlocked positions. A lock button (200) is movable between a first position in which the lock button (200) positively holds crossbolt (36) in its locked position and a second position in which crossbolt (36) is free to move. A drive lever (43) is provided for moving crossbolt (36) between its locked and unlocked positions. Lock button (200) is moved from its first to its second position upon rotation of a handle (130) so that a panic exit may be accomplished without manually unlocking lock button (200). In addition, lock button (200) is movable to a third position for holding crossbolt (36) in its unlocked position to provide an anti-lock out feature. Rotatable handle (130) includes a lock cylinder (63) therein.</p>
