Mankind - Redefined

Mankind - Redefined is an Institute main quest and achievement/trophy in Fallout 4.

Detailed walkthrough
Meet Father on the rooftop after The Battle of Bunker Hill. He will request for the Sole Survivor to attend the next Directorate meeting. There, Father will make it public knowledge that he is dying from an aggressive form of cancer, and that he will be appointing the Sole Survivor as his successor upon death.

Speaking with Father afterwards, he will state that it will take time for the scientists to accept that the Sole Survivor will become the new director, but will give assurances that the Sole Survivor will be the future of the Institute, and his legacy.

Finishing this quest automatically begins the next quest, Mass Fusion.

Bugs
The directorate meeting may never start. All the department leads will be sitting at the table waiting for Father's announcement, but he will only ever say that he has something important to say before he can talk to the player in private. PC players can use console commands to advance the quest to the next stage. This bug also occurs if any of the faction state (i.e killing a faction member) change after getting the quest, but before going to the meeting.
 * One thing that may bypass this bug; head back to where one first meets Father on the C.I.T. ruins after the aftermath of The Battle of Bunker Hill. If encountering Father for the first time, be sure to wait a while on the rooftop after Father beams back to the Institute. If one has already met him in the C.I.T. ruins and this bug occurs, go back to where one would normally meet Father on the roof of ruins; start firing a weapon around. After this, try fast-traveling back to the Institute and Father automatically begins his dialogue for "Mankind - Redefined", even though he is three floors above the Survivor upon first arrival to the Institute.