I have been reading a lot about Martin Majoor's typefaces lately. He wasn't happy with how Scala was being used so he designed Seria as his “literary” typeface. This was also in response to a request to make a second italic for Scala. He realized this wouldn't be possible with Scala so he designed Seria.

From what I can tell Seria is Scala with longer ascenders and descenders as well as an italic that isn't as sloped. I'm sure there is probably much more to it than that though. By making the ascenders and descenders longer he was able to make the second italic. The second italic was never publicly released.

I have read everything I can find but I can't figure out what other characteristics make Seria a “literary” typeface. I am also wondering what situations Scala would be inadequate for? The information I've been reading is from Martin Majoor's site. He has a lot of links to information about his typefaces.