Check your in your settings there should be a option to choose to re-open last session in there.

I had checked that box an still does not open the pages from last session. What's the trick?

Well I have to go back home when done at work and look at my settings but I know I saw there was a option there to do that. But if you don't have the privacy to clear cookies and history you can always click the option restore sessions and they should come back. But this assumes you didn't open a blank homepage and closed it before clicking option to reopen previous sessions. If you don't they will be gone if you try to reopen it again.

There is something that is not making this work. Yes there is that box ( Preferences/General/Startup) to check that says "restore previous session" and I have checked it. But upon new start up of Firefox, I still get only one tab open and it is home page

Have your Firefox session open with whatever you want it to open with, then Options -> Home...

...under "New Windows and tabs..." select "Custom URLs."

If all other pages are loaded in tabs, all instances of Firefox (including all tabs and windows), click "Use Current Pages" button.

This will automatically open all current windows and tabs of Firefox, sans about:options.

wilwood said

There is something that is not making this work. Yes there is that box ( Preferences/General/Startup) to check that says "restore previous session" and I have checked it. But upon new start up of Firefox, I still get only one tab open and it is home page

Any chance that you have Firefox set to clear your browsing history when Firefox closes?

If you clear browsing history, that clears your session data so there's nothing to restore when Firefox is opened again.

Thanks, that is what it was.