In order to address that question, he told about his journey to how he got to becoming an illustrator and later, an author. He said that first off, he always loved to draw. From the time he was a child, he also used his drawing to tell stories. He said that he created his first book when he was just 5 years old. But as he was growing up and planning his life, he tried lots of jobs -- print design and set up being one of the formative ones. However, in college, he thought that he should be a scientist. But, he found out that he just wasn't good enough in math. His professor suggested that since he was always drawing, he should transfer to the art department. After trying so many jobs and failing at most of them, being in the art program was liberating. (He could get a job doing what he was good at and actually interested in? What a concept!) What caught my attention, though, was how he admitted that having those early experiences gave him a broader knowledge of life and a better base for understanding people and telling stories. An illustrator is ultimately a storyteller.
He also told about how he goes about planning the pictures for a story book. Because he grew up with television and movies, he said he thinks cinematically. As the story goes along in his head, he "sees" what is happening in pictures in his mind. (Where an author uses words to paint the picture for the reader, an author/illustrator uses pictures to paint the scene without needing to use words. In fact, using so many words on the page that say what the picture portrays is redundant and boringly unnecessary.) So, as he is planning the story, he is already visualizing the action in his head, and then, when it comes time to draw the illustrations, they are already there.
One show in particular came about this way, "Parizade's Quest." I saw in my mind (mostly in visions through the night) the scenes, actors, costumes, and dances, then worked madly by day to put what I had already visualized onto paper. And just like an illustrator uses pictures to economize words, I could use songs instead of dialogue to move the plot along. Inspiration is miraculous!