Valentine's concept of introversion includes traits that contemporary psychology would classify as openness to experience ("thinker, dreamer"), conscientiousness ("idealist"), and neuroticism ("shy individual").
A long line of poets, scientists, and philosophers have also tended to group these traits together. All the way back in Genesis, the earliest book of the Bible, we had cerebral Jacob (a "quiet man dwelling in tents" who later becomes "Israel," meaning one who wrestles inwardly with God) squaring off in sibling rivalry with his brother, the swashbuckling Esau (a "skillful hunter" and "man of the field"). In classical antiquity, the physicians Hippocrates and Galen famously proposed that our temperaments—and destinies—were a function of our bodily fluids, with extra blood and "yellow bile" making us sanguine or choleric (stable or neurotic extroversion), and an excess of phlegm and "black bile" making us calm or melancholic (stable or neurotic introversion). Aristotle noted that the melancholic temperament was associated with eminence in philosophy, poetry, and the arts (today we might classify this as openness to experience). The seventeenth-century English poet John Milton wrote Il Penseroso ("The Thinker") and L'Allegro ("The Merry One"), comparing "the happy person" who frolics in the countryside and revels in the city with "the thoughtful person" who walks meditatively through the nighttime woods and studies in a "lonely Towr." (Again, today the description of Il Penseroso would apply not only to introversion but also to openness to experience and neuroticism.) The nineteenth-century German philosopher Schopenhauer contrasted "good-spirited" people (energetic, active, and easily bored) with his preferred type, "intelligent people" (sensitive, imaginative, and melancholic). "Mark this well, ye proud men of action!" declared his countryman Heinrich Heine. "Ye are, after all, nothing but unconscious instruments of the men of thought."
Because of this definitional complexity, I originally planned to invent my own terms for these constellations of traits. I decided against this, again for cultural reasons: the words introvert and extrovert have the advantage of being well known and highly evocative. Every time I uttered them at a dinner party or to a seatmate on an airplane, they elicited a torrent of confessions and reflections. For similar reasons, I've used the layperson's spelling of extrovert rather than the extravert one finds throughout the research literature.
Acknowledgments
I could not have written Quiet without the help of countless friends, family members, and colleagues, including: Richard Pine, otherwise known (to me) as Super-Agent RSP: the smartest, savviest, and menschiest literary agent that any writer could hope to work with. Richard believed unswervingly in Quiet, even before I did. Then he kept on believing, all the way through the five years it took me to research and write it. I consider him not only an agent but a partner in my career. I also enjoyed working with the whole team at InkWell Management, including Ethan Bassoff, Lyndsey Blessing, and Charlie Olsen.
At Crown Publishers, it has been my privilege to work with the remarkable Molly Stern and her all-star team. Rachel Klayman has got to be the most brilliant and dedicated editor in the business. She has been there at two in the afternoon and at two in the morning, spotting flaws in my reasoning and clunkers in my prose, and championing this book indefatigably. I also appreciate how generous Mary Choteborsky and Jenna Ciongoli were with their editorial talents. And I was fortunate to work with outside editor Peter Guzzardi, who has terrific instincts and a knack for making criticism sound delightful. My heartfelt thanks to all of you. This book would be a shadow of itself without your efforts.
Special thanks too to Rachel Rokicki and Julie Cepler for the creativity and enthusiasm they brought to the Quiet cause. And thanks to Patty Berg, Mark Birkey, Chris Brand, Stephanie Chan, Tina Constable, Laura Duffy, Songhee Kim, Kyle Kolker, Rachel Meier, Annsley Rosner, and everyone else on the team at Crown.
