Dragons is a two-piece Blu-Ray/DVD package that was released on November 15th, 2011.
DVD covers
The package is comprised of a twenty-two minute short Gift of the Night Fury and the eighteen minute short Book of Dragons.[1]
Gift of the Night Fury
Gift of the Night Fury is a How to Train Your Dragon Christmas special, directed by 
Tom Owens on Wikipedia. It was released on November 15, 2011, on DVD and Blu-ray, along with Book of Dragons. Based on How to Train Your Dragon, the short takes place in the middle of preparing for the Viking winter holiday version of Christmas, Snoggletog, when suddenly all the dragons inexplicably go on a mass migration, save for Toothless.
Book of Dragons
Book of Dragons is an 18 minute short film, based on How to Train Your Dragon, and was released on November 15, 2011, on DVD and Blu-ray, along with Gift of the Night Fury. The short shows Hiccup, Astrid, Fishlegs, Toothless and Gobber telling the legend behind the Book of Dragons and revealing insider training secrets about new, never before seen dragons. The short shows a total of 14 dragons, each spread into 7 classes: Stoker (Terrible Terror, Monstrous Nightmare), Boulder (Gronckle, Whispering Death), Fear (Hideous Zippleback, Snaptrapper), Sharp (Deadly Nadder, Timberjack), Tidal (Scauldron, Thunderdrum), Mystery (Changewing, Boneknapper) and Strike (Skrill, Night Fury).