I have not watched Onward yet, and based on the trailer I am not certain whether or not I will enjoy the movie (I can already tell that, if all goes well, I will love Soul).

The being said, I was delighted by The Art of Onward, mainly because the book allowed me to discover the concept paintings from several very talented Pixar concept artists. In fact, was especially seduced by the art of Carlos Felipe Leon, which, for some reason, I find particularly striking.