They say that Mars Inc. culture is unique. That is an understatement. The privately held company is a mix of uniformity, tight focus on cost control, and limited public exposure. The begining of the interview process is typical, HR telephone interview, telephone interview with the hiring manager, IQ tests on-line etc. However, the in-person interview process can only be described as intense. It is a mix of applied case study & management presentation and panel behavioral interview.
Preperation. Know their five principles. Understand their business, the key drivers for the position - why are they hiring, and practice presentation skills to management. The case study is timed so you will need to work well under pressure. Presentation skills should be highly focused and organized. Be prepared for questions like "Why should I hire you?" and "Why so many jobs?" They will involve 10+ people in the interview process so the panels could be 4-6 people. Also have an extensive listing of questions for the panel and case study team. Again, be highly prepared.