.doc File — Microsoft Word Document (Legacy)

The DOC file format is the proprietary binary document format used by Microsoft Word from 1997 through 2003. It stores rich text content including formatting, images, tables, headers, footers, page numbering, and embedded objects in a binary structure based on the Microsoft Compound File Binary Format. DOC files can contain macros written in Visual Basic for Applications (VBA), which historically made them a vector for macro viruses. The format supports complex document features like mail merge, revision tracking, comments, and cross-references. While largely superseded by the XML-based DOCX format starting with Office 2007, DOC files remain widely encountered in legacy systems and archives. The format was partially documented by Microsoft and reverse-engineered by open-source projects to enable interoperability. Many modern word processors can still read and write DOC files for backward compatibility.