I had a client send me an .ai image which I imported. I found out that the font used in it was Garamond Serial Bold. I had Garamond installed so used that, but it's slightly different (a little heavier and the serifs are slightly different).

So I found Garamond Serial Bold, downloaded it and installed it. In font viewer (Windows 10) I can see 2 distinct fonts installed - Garamond, and Garamond Serial Bold. Yet (after shutting down Inkscape and restarting) I can still only see Garamond and there's no extra style under it. 

So where did the newly installed font go? I haven't tried rebooting the computer yet, but I've never had to do that after installing any other font - only restarting Inkscape.

If you are using windows 10 you may need to go back to the extract/download folder and right click on it to bring up  a menu, then select 'install for all users'.  Then reinstall.  (basically have to start over).

If this doesn't work, please indicate your op sys and what version of inkscape you are using, so someone on here can better assist you.

Ah-ha. Install for all did it - thanks. Funny, I've never had to do that before and I'm the only user on this computer.

Install for all users is only needed for Windows 10, and Inkscape versions before 1.0.  (The problem is a bug with something Windows uses to handle fonts - started with a Windows update a year or 2 ago.)

This bug is fixed in stable 0.92.x 
https://inkscape.org/release/inkscape-0.92.x/?latest=1

Just upgraded to 0.92.4, but the same issue remains. Still need to install for all users for the fonts to show.

On a positive note, it does seem that Inkscape is faster to load and to export which is great. That's always been a bugbear of it in the past.

0.92.x = 0.92.4 with bug fixes (upcoming 0.92.5)

From release note draft

Notable bugfixes and crash fixes

• As of Windows 10 (version 1809) fonts are installed into a new user-specific folder by default. Allow Inkscape to recognize those fonts.

So that draft would be for 0.92.5, which does not exist yet.  And this is actually the first I've heard about it.

This problem is NOT fixed for 0.92.x.  As far as I know, "x" means any number.  Apparently it's only fixed for the future 0.92.5 and above.

What I wanted to say to trogladyte is that install for all users is a short term fix and will not be needed much longer.

No, Aero is right, bug is fixed in 0.92.x.

("0.92.x" means 0.92.x branch and is the current stable development branch for all 0.92.x versions including the upcoming 0.92.5. The link given points to the latest snapshots of that branch and has the fix.)

Do you mean that it's now been fixed in versions where it wasn't fixed before?  So that if I go back and download 0.92.1, it will work properly?

If so, this is the first time I've ever seen inkscape go back and fix older versions.

If not, please explain in a simpler way what the "x" means.

You can think of a code "branch" literally: It continues to grow and therefore changes over time. So the 0.92.x branch spawned (past) versions 0.92.0 to 0.92.4 and it will spawn (future) versions 0.92.5 to whatever will be the last 0.92.x version we will release.

The fix for the font issue landed somewhere in between 0.92.4 and the (yet unreleased) 0.92.5.
However the branch 0.92.x has (as of now) the fix for this issue.

So the "x" has nothing to do with version numbers.  It only means 'the most current version of the code' ?

Yes, most commonly it refers to branches and unless specified in more detail the most current version of a branch is referred to.

Thanks for explaining!  ❤