First published in 1954 -- and, portentously, re-published in 1971 as part of the Lin Carter-edited Ballantine Adult Fantasy series -- The Broken Sword is one of a handful of novels that can lay claim to being the most significant influences on Gary Gygax and, thus, Dungeons & Dragons. The Broken Sword is set during the age of the Vikings and describes the tragic lives of two people: a boy stolen by the elves and raised among them to handle the iron they themselves cannot and the changeling who takes his place. Each comes to hate the world in which they were raised, with terrible consequences. The Broken Sword is not a happy book, but it's extremely well-told and reminds one, not coincidentally, of the Norse sagas from which Anderson drew significant inspiration.
Personally, I find The Broken Sword interesting, because it provides a plausible alternate avenue for the treatment of elves and half-elves in D&D, particularly the latter. Given that half-elves first appear in Supplement I, a book that also introduces several other Anderson-inspired game rules (such as the paladin class), I don't think this is implausible. Anderson's elves share many characteristics with Tolkien's, but then both authors looked to Norse legends as their models. Anderson's elves are far more passionate and martial than are Tolkien's. They're also more alien and removed from the affairs of the mortal world of which they are not a part. I very much like their portrayal and my own interpretations of the race owe a lot to Anderson, much as I suspect Gygax's did as well.