<p>I have a netbook running Linux and a large collection of computer books and reference material as HTML. I'd like some compact way of storing these books which can be browed without unpacking them first. This would save space and reduce wear on my small SSD.</p>

<p>If there was some way to convince Firefox to browse files contained in ZIP file, this would be ideal. (I know iCab (Mac) had a web archive format that worked this way.)  Perhaps a Firefox plugin? A small web server that can serve directly from ZIP files? Some magic FUSE module? Does anyone have any ideas?</p>

<p>On my PDA (which the netbook is largely replacing) I used iSilo for this, but it's not available for Linux, its conversions are lossy and it costs money. </p>

You can use
OpenOffice.org
to open the html pages, and then save them as OO documents. OO documents are essentially a zip files.
Another option is to use OO to save as pdf.
You can even do this from a command line using this
OO macro
.
Same with
AbiWord
- you can use it on
commandline to convert
.
In the AbiWord example there is shown how to convert all files in a directory to a desired format (pdf). Then you can use
pdftools
to merge all pages in one document.
Also, I do not know what windows manager your laptop has, but if it is KDE, konqueror (the file and web browser for KDE) opens web pages from inside a zip file w/o any problem.
Most probably Gnome's Nautilus can do this as well (I have no Gnome here to test).
Have you ever tried to open a zip file with whatever file manager you have, and then click on a web page inside it?