He says none of the artists in the book were paid for their drawings. The proceeds from the sale will go to the organisation which aims to encourage city sketching throughout the world.
Mr Dewhurst says love for drawing was the reason he went into graphic design but, lately, it has become more of a computer job.
"I sit at the desk staring at the computer and so I started to get out with a sketchbook. It's quite refreshing looking at things from a distance instead of staring at things all the time," he says.
Typically he will sketch from about 10 minutes to an hour, quickly drawing transient objects such as the Volvo Ocean Race yachts.
"I just try to capture the atmosphere or the feeling. It's not too finished," he says.
The father of three says he would like to paint some day but things are quite hectic at the moment between family and work. Initially his children would complain as soon as he got out his sketchbook, but now they come along and do their own sketches.
"The girls are particularly good," he says, adding that sketching has really made him stop and take a good look at the things going on around him.
"Now, I'm just trying to sit down and enjoy it more and see it better," he says.
Are you an urban sketcher who has drawn an Auckland scene? Send your drawing to news@theaucklander.co.nz for the chance to have your picture published online
Check out Murray's art at www.aucklandsketchbook.com and on Facebook
Book: The Art of Urban Sketching: Drawing On Location Around The World, Gabriel Campanario.