What are prohibited transactions?

What are prohibited transactions?
Understanding what constitutes a prohibited transaction is very important when it comes to making investments within your IRA. The IRS defines the prohibited transaction as follows:
"Generally a prohibited transaction is any improper use of your account, IRA or annuity by you, your beneficiary or any disqualified person. Disqualified persons include your fiduciary and members or your family (spouse, ancestor, linear descendant, and each spouse of linear descendant). "IRS Publication 590