This is an overview of TIFF 5.0, which is formally specified in Tag Image File Format Specification, Revision 5.0 FINAL, An Aldus/Microsoft Technical Memorandum, 8/8/88, hereafter called 'the specification'. This note interprets the content of a TIFF file itself, not the content of the specification. One of the great things about the Aldus/Microsoft TIFF specification is that it contains much tutorial and historical information. One of the problems with the document is that this wealth of information obscures the compliance requirements for writers and readers. TIFF revision 6.0--although imminent--is not yet standardized and therefore is not addressed by this note.