What exactly is our relationship with insects? Are they more beneficial or harmful? What role do they play in the world? What are the effects of climate change: Will the number of insects continue to increase? This book discusses the beneficial and harmful effects of insects and explains their development and significance for biodiversity. This second, fully reviewed and enlarged, edition provides new insights, especially about the value of specific insect species that are generally seen as pests (e.g. ants and moths), as well as an extended chapter on the development of insects and especially their decline in different regions in the world, the industrialized countries in particular. Numerous info graphics show connections between changes in the environment due to human expansion and the number of insects and species. Studies from the US, Canada, Asia, Africa, Europe and Switzerland are used to point out the dramatic reduction of biodiversity. New tables illustrate these developments. The glossary as well as the insects index is extended, the text, tables, pictures and graphs provide even more well-rounded image. Readers will find the argumentation even more clearly and detailed.