Fiduciary responsibility is the highest legal standard of care that professionals owe to those who place trust in them. It requires accountants, auditors, and lawyers to act in their client's best interests with complete honesty and fairness — but this duty is always subordinate to the law. Where compliance with a client's wishes would require violating the law, the fiduciary duty yields. It is fundamentally about acting as a trustworthy guardian of another's interests.