I've just added some mp3 files to iTunes by selecting "Add to library". The songs show up in a smart playlist I have for "Recently added to library". I can see their details and I can play them by clicking them. I have checked that media kind is set to "Music". However, they don't show up in my library. If I search for one of the titles within 'Music' I don't get any results. If I browse under the artist, nothing is there. Really strange. I do have iTunes Match, so I'm wondering if there could be some kind of delay, but normally songs do show up in my library before they've been added to iTunes Match, so I can't see why this would stop them appearing. I've tried quitting and re-starting iTunes a couple of times... any ideas?