I loved getting new stories from all of the Rick Riordian Presents series.  I have read at least one book in most of the series, but not all.  Stories I knew were easy to jump back into the characters and action, like with Gum Baby, or Sal.  For stories I had not read yet like Storm Runner and Dragon Pearl, it was easy enough to grasp what was going on, and exciting enough to make you want to get back to those unread series.  Plus the new Irish story from Riordian himself.  Loved it.  Plus, since this is all short stories, it makes it great for long and short car rides this holiday season.