Somebody should make a FAQ for this question, I seem to spend half my life answering it.
Regarding multiple HTML files:
1) If your collection of HTML files includes a file that has links to all the other files:
- Download the beta version of calibre and simply add that file to the GUI.
The GUI will automatically create a zip file with all referenced HTML files and the ZIP file will also contain an OPF file that references the HTML files. You can then use "save to disk" to save the zip file to somewhere on your disk. Unzip it and use the opf+html files in whatever program you need to.
2) If your collection does not have such a file, it takes two minutes to create one. It will have the form:
Code:
<html>
<body>
<a href="file1.html">File 1</a>
< a href="file2.html">File 2</a>
.
.
.
</body>
</html>