Ah, the Cosmere. No living author has so successfully created a multiverse as Brandon Sanderson, or come up with such wildly varying worlds to fill it with. 
 And given how prolific the man is, it's not surprising that -- in addition to his many novels -- he's also produced a string of novellas and short stories set in his Cosmere worlds. And finally, they can all be found together in "Arcanum Unbounded: The Cosmere Collection," which strings together every story in the Cosmere thus far that can't be used to prop up a couch, from the Hugo Award-winning "The Emperor's Soul" to a brand new novella. To a fan of Sanderson's work, this is like a box of fine chocolates. 
 The stories are arranged according to the worlds they are set in, with most of them being in the Scadrian System (the world of Mistborn) and two of them set in the Selish System (the world of "Elantris" and "The Emperor's Soul"). These stories tend to be strongly attached to the novels Sanderson has written in their worlds, such as a story about Raoden hearing what Ashe was getting up to during the battle for Elantris; the post-death adventures of Kelsier; and his Allomancy training under Gemmel and his first true battle. 
 But there are other stories that stand more alone -- a master forger is called upon to create an artificial soul for the assassinated emperor; the invasion an island where magical birds grant powers to their masters; and an awe-inspiring bounty hunter in a haunted forest who seeks a legendary assassin. It also contains an excerpt of the "White Sand" graphic novel, and the prose draft that inspired it -- a story about Kenton, a young man determined to be a sand master. 
 And yes, there's a new novella here: "Edgedancer," set in the world of Sanderson's Stormlight Archives series. Lift and her spren Wyndle leave the palace unexpectedly, and end up in the underground city of Yeddaw (which allegedly has ten varieties of "awesome pancakes"). But of course, the city also has the dangerous man she calls Darkness -- and when he learns that she's there, Lift finds herself enmeshed in a new and deadly situation. 
 In addition to the stories themselves, Sanderson writes an introduction where he describes his early writing career and the inspiration of the Cosmere, and a postscript where he discusses its concepts and publication history. For instance, for "The Emperor's Soul," he discusses how Korean stamps were a shaping influence on the tale. And before each new world is explored, he includes a brief overview of the planet, its quirks, and the Shards that have shaped it. 
 Brandon Sanderson's fictional worlds are always very complicated and imaginative, and anything smaller than a doorstopper tends to leave you desperately craving a fuller exploration of whatever world the story takes place in. So "Arcanum Unbounded" makes an outstanding accompaniment to his novels -- some of the stories further flesh out those novels ("Mistborn: Secret History"), while others take the readers to entirely new worlds ("Shadows For Silence In The Forest Of Hell"). 
 And honestly, almost all of the stories are outstanding, with "Allomancer Jak and the Pits of Eltania" being the one mediocre tale of the bunch. They show the wide variety of magics that Sanderson's fertile imagination is able to conjure, his robust writing style with plenty of detail, and his nimble wit ("please don't get yourself killed. It would be traumatic. Why, I think it would take me months and months to get over it!"). Each story winds through at a fairly quick pace, with some dark twists (Kelsier being trapped in the Well) woven into their fabric. 
 And his characters are a thoroughly likable bunch. Some -- like Kelsier, Ashe, Raoden and Lift -- are from the novels he's written, and these stories allow for greater fleshing-out of their personalities. But just as engaging are the new characters he introduces, such as the practical Dusk, the butt-kicking innkeeper/bounty-hunter Silence, and and the clever and cunning Shai. 
 "Arcanum Unbounded" is an essential accompaniment to Sanderson's Cosmere tales -- when he isn't building on his previous works, he's crafting new tales in richly-imagined worlds. A delight for fantasy fans.