An Outline of Entomology

Why insects are the most successful and most diversified of all creatures? What is their economic importance to our welfare? Do they have any detrimental effect? What type's external features come to your mind while you hear the word arthropod? Which external feature(s) do you think that is responsible for their interaction with their surrounding environment? Does the classification scheme for arthropods vary from other animals? What are the most common and recently used insect orders identification keys? This work briefly elaborates all the mentioned questions and more.