An initial multiple-choice problem solving test (McKinsey PST is extensively covered on the internet) followed by three rounds of interviews: one in my country of residence (an AP and an Associate) and two in the hiring office (a mixture of EMs, APs, and Partners). All interviews lasted for one hour and involved solving a case and discussing your personal experiences of leadership, team work, working under stress, etc.. The cases were all rather standard, and the interviewers were very involved and helpful in getting you to cover all aspects of the case and arrive at the right conclusions - no leaving you to wander in the dark for 20 minutes and then announcing that the time is up. Actually, I found discussing my personal experiences more of a challenge, as the interviewers required well-defined, concrete examples. Throughout the process, the staff at all levels appeared extremely intelligent, level-headed, and fun - I am confident they would have made great colleagues.