Simplify the following text for a Grade 18 native English-speaking person.
Original: Foster 's most recent book , The Ecological Revolution : Making Peace with the Planet , is a collection focusing on the ecological crisis , and includes essays on global warming , peak oil , species extinction , world water shortages , global hunger , alternative energy sources , sustainable development , and environmental justice .
Simplified: Foster 's most recent book , The Ecological Revolution : Making Peace with the Planet , examines the ecological crisis , and includes essays on global warming , peak oil , species extinction , world water shortages , global hunger , alternative energy sources , sustainable development , and environmental justice .