That’s half of chemistry in one sentence: atoms that don’t have enough electrons in the outer level will fight, barter, beg, make and break alliances, or do whatever they must to get the right number.
-- Sam Kean (chapter 1)

Importance: This sentence is crucial to understanding the nature of elements, and the way that atoms function. This understanding is essential to the reader's comprehension of much of this book, as Kean's discussion of elements, matter, and the nature of the universe often depends and centers upon the way atoms behave with one another. The need for atoms to have the right amount of electrons on their outer levels is what drives much of their behavior and it explains why some atoms are more likely to bond with one another, thus creating the types of matter that we are familiar with and which are often key in the creation of life, such as water...