Passwords for single pages

The functionality you describe does indeed still exist in core WP 3.5.2 for both Posts and Pages in the Visibility option box. If you’re not seeing those options then perhaps your WP admin has been customized? Or, the whole Publish section may be collapsed; mouseover the Publish title (top right in the Edit screen) and see if there a little downarrow to the right that you can click to expand it.

There is an arrowlet in the Publish box, but it turns out that I already had the maximum window open; I would send you a tiff if I knew how.

Is there a toggle deeper in the settings menu covering this function?

I did take a series of mini-courses in WP but to the best of my knowledge did not customize this area.

You can try testing it with a base WP setup to see if it’s a plugin. Switch to the TwentyTwelve theme and deactivate all plugins, then see if the Private options appear on the post edit screen. If they do, then something on your site is changing the default behavior. Switch back to your theme and test again; then do the same with each plugin, reactivating them one by one and testing after each new one is active to see where the culprit is.

If you don’t see the options even with the base WP setup then it’s something to do with how you have your screen options or browser window configured. Here’s the codex on these options:
https://codex.www.ads-software.com/Content_Visibility

That did it as far as stage 1: password-protecting the page. But now that it’s password protected I don’t see that promised message making a prospective poster enter a password. As I read the codex item, this should appear on the protected page as published. Am I reading wrong? Does the prospective poster have to log in as an editor/admin/whatnot and then enter the password again? Sorry to be so thick.

If the page is marked private and you are viewing it from the front end, then it will prompt for a password to any user who is not currently logged onto the site. Did you log out of the browser session before trying to view it? If you’re still having trouble then please send the link to the page so we can check it out.

“If the page is marked private and you are viewing it from the front end, then it will prompt for a password to any user who is not currently logged onto the site.”

I have a page marked private. When I view it from “the front end” (as a non-logged in visitor to the site, right?) I get a 404 error. This happens wether I mark the page as “private” or “password-protected.” The code inserting a comment box appears to be correct.

Yes, as a non-logged in visitor to the site.

Has the page been published? If it’s still in Draft mode it won’t show up on the front end.

I’m not sure what you mean about code in a comment box.

When I look at the page in question edit mode, this is what I see:

This page is dedicated to the behind-the-scenes work of the Foundation. Those entitled to entry may log in here:

[contact-form subject='[Pelle%26#039;s Place’][contact-field label='Name' type='name' required='1'/][contact-field label='Email' type='email' required='1'/][contact-field label='Website' type='url'/][contact-field label='Comment' type='textarea' required='1'/][/contact-form]

When I click on the page in the navigation menu, I still get a 404 error. I must have somehow broken the link within the site while tinkering with getting the log-in box to work. I can erase the offending page and create a new one, but when I do I just get the plain text above and no indication HOW the visitor is supposed to log in.

The main reason that a 404 would display is if the page has not been published.

Those shortcodes imply that you’re using a plugin for access to the site. If so then it’s hard for me to provide guidance since I don’t know your setup. You could try posting your question on the plugin support forum.

Or there might be an easier way for you to get what you want – this codex could help if all you want to do is provide specific text along with the password prompt:

https://codex.www.ads-software.com/Using_Password_Protection#Password_Form_Text

Remember that the password on a password-protected post or page is not the same as the password that a registered user inputs to log onto the front end of the site. That may be causing some confusion for you. A registered and logged-on user will still need to enter any required page-specific password.

Maybe all that will help; I doubt I’ll be able to provide much further guidance since you have yet to provide a link to the site and so all along I’ve been flying blind which isn’t much use to anyone.