answer:You really do have to go back to school. To teach at a university – which is what I’m assuming you’re talking about – you have to have a graduate degree, though I’m unsure of exactly which degree you would need in your region. Because you already have a degree, you might be able to get into a grad program that’s not business; you might have to agree to take a few classes in the area first for not majoring in it, but you wouldn’t necessarily have to get a second undergrad. You certainly can write a book, the question is, will anyone publish it? And if you’re hoping to have it be taken seriously as work, then you need the degree. If you’re just hoping to sell lots of books, then you might not need as many credentials so long as it was populist enough, but even still, it’d be an uphill battle to get publishers to publish it.