tools can decompile a WinHelp file into its source documents: HPJ, CNT, RTF, BMP, and SHG. An HPJ file is the project file that is created and edited in the Help Workshop (or a third party help authoring tool). The HPJ contains information about what RTF files to compile into the help, the MAP IDs and Aliases that provide links from a calling application to the help file, and help file appearance (window size, default buttons, color schemes, etc.). The CNT file provides the table of contents for the help file. An SHG file is a "SHED" graphics file that essentially creates an image map of help calls for a graphic file (e.g., a BMP). A number of tools can read and explore these files. (See, for example, Help to RTF and winhelpcgi.) Source files and compilation Source files required to compile a .hlp file consist of one or more documents in Rich Text Format and a help project file with the extension .hpj, along with any image files (.bmp, .wmf, or .shg) that are used within the Help file. An optional table of contents file with the extension .cnt can also be created for use with the .hlp file. Within the .rtf files, topics are separated by page breaks. Each topic has a series of footnotes that contain information for the help compiler: # footnotes contain the topic ID (used to create links to that topic). $ footnotes contain the topic name as it displays in the table of contents, index, and other locations. K footnotes contain keywords for the index. A footnotes contain See Also keywords. * footnotes contain build tags. + footnotes contain browse sequence information. ! footnotes contain topic entry macros. Only the # footnote is required. All others are optional. Text in each topic can contain limited formatting, including bold text, italics, and colors. Superscript and subscript are not allowed. Jumps between topics in the same Help file usually appear in the source document as double-underlined text (green by default, though this can be overridden) followed by a topic ID in hidden text. Popup links appear in the source document as text with a single underline (also green by default) followed by a topic ID in hidden text. (In the .hlp file, the jumps show up as green text with a single underline, and popups show up as green text with a dotted underline.) Images