Can I browse HTML files locally when I'm offline?

If you do not use Microsoft Windows, the answer is usually "no problem!" Just use the "Open File" or equivalent option on the file menu of your web browser, instead of "Open Location" or "Open URL".

If you use Microsoft Windows, and particularly if you use Netscape, this may be a problem. Some web browsers will refuse to run unless there is functioning Internet software running on the system. Netscape offers a solution to this problem in the release notes to version 1.1 of their product. Essentially, you can install an "empty" Internet interface (winsock.dll) that keeps Netscape happy.

World Wide Web FAQ