Although the author doesn't say it, he does come across as implying that books don't emphasize the curiosity aspect. While this is true for Nonviolent Communications (NVC), I have seen it in other books. Here is an example from Difficult Conversations (DC):

> There’s only one way to come to understand the other person’s story, and that’s by being curious. Instead of asking yourself, “How can they think that?!” ask yourself, “I wonder what information they have that I don’t?” Instead of asking, “How can they be so irrational?” ask, “How might they see the world such that their view makes sense?” Certainty locks us out of their story; curiosity lets us in.

The heading of that section is Move From Certainty To Curiosity

I've always said that the NVC book is great on teaching the how but not the why, and that DC is the exact opposite. The latter gives you a lot of insight, but with a lot less practical guidance.

Similarly, the book Crucial Conversations specifies the following 4 ingredients to listening:

- Be sincere

- Show curiosity

- Stay curious (i.e. don't react)

- Be patient