The rationale for the 1997 edition was that, the more people that know about the lifestyle of plants, the more likely it is that they will appreciate what has to be done to preserve this component of the biosphere upon which our survival depends. A secondary aim was the hope that people would discover that knowing more about how plants work is not just useful but also fun.

This second edition is addressed primarily to an audience of students of plant sciences but also to keen gardeners, naturalists, or anyone with questions about why the Earth is green, how plants defend themselves against diseases and predators, how they combat the stresses of constant exposure to the environment, and how climate change is affecting plants.

The general alarm voiced in the 1997 edition about the deleterious effects humans are having on our environment through global warming, deforestation, overgrazing by domestic animals, overcropping of arable lands, and pollution of land, water, and the atmosphere, is now, more than 10 years on, more clearly focused. Thus, in addition to making the book's original contents consistent with the most recent knowledge, material has been added to educate students of all ages about how human activities are impacting the lives of plants – how plants are affected at the physiological level by changes to our environment, such as through increasing concentrations of greenhouse gases, higher temperatures, longer growing seasons, increasing ocean acidity, changing water economy of the Earth, and pollutants such as ozone.