Confidentiality of tax information restricted, with statutory exceptions permitting disclosure for prosecutions, government functions, audits, inquiries and system operations. Particulars in statements, returns, accounts, documents, records of evidence or proceedings under the Act are confidential and officers are not to be compelled to disclose them, subject to specified statutory exceptions allowing disclosure for prosecutions, implementation of the Act, service of process or recovery, civil suits involving the government, audits of tax receipts or refunds, inquiries into officer conduct, necessary intergovernmental tax purposes, lawful exercise of other statutory powers, disciplinary inquiries against certain professionals, contracted automated system operations under confidentiality, compliance with other laws, and publication of class-level tax information where the Commissioner so approves.