Core marketing, accounting, finance, and microeconomics. In more or less that order. Others include behavioral economics&#x2F;decision theory--or at least read Ariely or Thaler&#x27;s book. Other possibilities include organizational behavior, negotiation, pricing, business strategy. One general comment is that, if you&#x27;re just looking at a few courses, you&#x27;ll probably get more out of in-person courses that have case studies and&#x2F;or group discussions, role playing, etc. and just read a book to cover more lecture-oriented material (like microeconomics usually is).