The first omnibus edition of 4, each containing 2 of the Cheysuli series, Shapechanger's Song has the first 2 books originally printed separately as Shapechagers and The Song of Homana.
In Shapechangers, the main character is Alix, the daughter of a princess and a Cheysuli - shapeshifter - warrior, is kidnapped by on of her then unknown (by her) Cheysuli relatives and finds herself caught up in an ancient Cheysuli prophecy. Meanwhile her childhood friend, the prince of Homana is torn between rescuing her and a war between Homana and the sorcerers of Ihlini.
The Song of Homana takes place several years later with the crown prince of Homana, Carillon, returning from exile, ready to retake his throne from the usurping Ihlini. With a Cheysuli warrior at his side, he returns to a land oppressed and still unready to accept the Cheysuli people to raise an army of both the Homanan and Cheysuli peoples.
Impression:Shapechangers was definitely my favorite of the two. Not that Song was bad, it wasn't. But is was definitely a slower read for me. First there was the switch in characters, from Alic to Carillon, which was not only a character shift but also a shift in gender since Alic is female and Carillon is male. The second jolt is in pov: Shapechangers was written in third person and Song was written in first. I think if I had the 2 or 3 years that usually pass between books, the transition wouldn't have been such a bump for me.
That being said, I picked up all 4 omnibuses of this series because 1) I liked Roberson's Del and Tiger series, and 2) I'd been wanting these books for some time. She does not disappoint thus so far (I've just started book 3). The characters are well developed and change over time in believable ways; the setting is rich, unique, and consistent; and, despite the passage of years between books (book 3 finds one of the children as the main character and near grown), she writes in such a way that you can see the flow from one book to another. I can definitely see myself reading these again one day.