Husband-and-wife collaborators Jim and Kate McMullan have followed up their award-winning picture book, I Stink!, narrated by a feisty city garbage truck, with I'm Mighty!, in which a tugboat struts his stuff on an animated tour of his harbor.

PW: Just how did these affable vehicles spring to life?

Kate McMullan: Well, I Stink! grew out of the fact that I had become obsessed with the truck that picks up our garbage in Manhattan—mainly because it kept waking me up early. So one day I decided to go down and see just how it makes all its noise and for the first time saw how the truck really works—mashing up huge bags and carting them away. I began going down to the street on a regular basis to write down the truck's sounds and I got to know the men on the truck. When I told them I was writing a children's book, they were eager to tell [Jim and me] all about their work and they became friends of ours.

PW: Did a first-hand knowledge of the truck also inspire the book's art?

Jim McMullan: Yes, I knew about Kate's investigative reporting and one day I went downstairs with her, wondering what I could get out of the truck visually. I saw a face there right away. The brace in the middle of the truck became a nose, the lights on either side of it were like nostrils, the windows were eyes and in the huge bumper, filled with rivets, I saw a chin with stubble. I suddenly had this Jimmy Cagney face and it all came together—and Kate and I realized we were thinking about the same character.

PW: Did the idea for I'm Mighty! grow directly out of I Stink?

KM: It was somewhat of a natural segue, since tugboats sometimes haul garbage away. They seem like great little magicians to be able to do what big boats just can't do. And, like garbage trucks, they make a lot of noise.

JM: I grew up in various seaports, including Shanghai and Vancouver, and I have always loved tugboats. To me they represent all that is glamorous about harbors, and recall the busy harbors of the 1930s and '40s, when lots of people crossed oceans by boat.

PW: And was the hero of I'm Mighty! also inspired by a real-life vehicle?

JM: Yes, but we were researching this book just after 9/11 and we weren't able to get onto a tugboat in New York harbor because security was so tight. On a whim, I called up a tugboat company in Boston and told them we were working on a children's book and they told us to come on up anytime. So we did. Visually I find tugboats very interesting and, looking at this one, I saw the big front bumpers as lips and the rest followed from there.

PW: As you collaborate, do you develop the story together?

JM: One of the advantages of working together at a very early stage, before the story is completely nailed, is that I can do sketches. I first sketched the truck and tugboat in various situations and in that way I like to think I contributed a bit to the story.

KM: It's true. It is wonderful to have Jim's sketches early on so that I can think visually. But the text needs to be pretty solid before he does the final art.

PW: Are you planning on rolling out with any other personified urban vehicles in the future?

KM: Actually, we're going rural. We spent time on farms this summer and became tractor groupies, listening to tractors to discover what they have to tell us.

JM: A tractor is to the rural landscape what a tug is to the harbor. They're both historical and in a way quite romantic. And we found a similarity between the people who drive garbage trucks and those who operate tractors in that they are both so happy for the attention and so eager to talk about what they do. Many farmers feel that their very important activity is largely being ignored today. There really is a poignancy about that.