Plants and algae are essential for life on earth as it exists today. They provide our world with oxygen and food, contribute an essential part of water and nutrient cycling in ecosystems, provide clothing and shelter, and add beauty to our environment. Some scientists believe that if photosynthetic orrganism exist on planets beyond our solar systems, it could be possible to sustain other forms of life that depend upon them to survive. Botany today plays a special role in many interest of both major and nonmajor students. For example, in this text, topics such as global warming, ozone layer depletion, acid rain, genetic engineering, organic gardening, Native American and pioneer uses of plantsm pollution and recycling, house plants, poisonous and hallucionogenic plants, nutriotional values of edible plants, and many other are discissed.