A Goodreads user asked:
Do you need to read the first series to understand the plotline?
Elizabeth McCoy I started with The Warrior's Apprentice -- Shards of Honor was out of print, and Barrayar hadn't been published yet -- and it was just fine. Jump in here and go back to the Cordelia books later, as you like!
Miriam You can read and understand this book as a stand-alone, although you may enjoy some of the references to events about his parents if you read Cordelia's Honor (omnibus with Shards of Honor and Barrayar) first.
Dave You *can* read this first. I did and enjoyed it, but I think I would've enjoyed it more read Cordelia's Honor first. I recommend starting there, if possible.