A Children's Book that Focuses on a Social Issue

One of my favorite children's book is Dr. Seuss's The Lorax, which concerns environmental issues.  The Lorax is about the decline of an imaginary land home to the Lorax, the Once-ler, and beautiful Truffula Trees.  In a flashback, the Once-ler tells a traveling boy how this once beautiful land became desolate.  The Once-ler narrates that he was entranced by the colorful and wooly Truffula Trees.  One day, he chopped one day and a made a multipurpose garment, a Thneed.  Thneeds were in such high demand that the Once-ler had open more shops to accommodate the demand.  However much the Lorax protested, the Once-ler ignored him, spurred by greed and and success.  But the Lorax's warnings were true and eventually all of this land's natural inhabitants had to leave to find a new food source, clean water, and clean air.  The last Truffula Tree was chopped down for more Thneeds and the Once-ler loss his business.  Back in the book's real time, the Once-ler has lost his once beautiful home and gives the boy a Truffula Tree seed.  The Lorax has been criticized for being too gloomy unfair to certain industries.
It is clear that in The Lorax, Dr. Seuss is commenting on the greed of big businesses and its consumers.  On a smaller scale, The Lorax is about greed and instant gratification.  For both children and adults, The Lorax criticizes the extent to which we desire something and the consequences of getting it.  I think this is a good book of people of all ages.  It makes children and adults accountable for what they want.  In The Lorax, the consumers of Thneeds may or may not have known where their Thneeds came from or why they even wanted it.  The book is also very specific to environmental and consumer issues.  The Lorax claims that he "speaks for the trees, as the trees have no tongues."  The book obviously encourages more people to be environmentally friendly, which includes being a responsible consumer and knowing what corporations and their actions they and supporting as consumers.
I reread The Lorax in an biology class a few years ago.  As a child, I did not recognize the messages in the book, but The Lorax comments on our everyday actions as consumers and inhabitants of the earth.  I think it's a friendly book for children that can teach them to be more environmentally conscious, because their actions are going to have an increasing effect on big businesses and the environment.