Our "thirty-is-the-new-twenty" culture tells us the twentysomething years don't matter. Some say they are a second adolescence. Others call them an emerging adulthood. Dr. Meg Jay, a clinical psychologist, argues that twentysomethings have been caught in a swirl of hype and misinformation, much of which has trivialized what is actually the most defining decade of adulthood.
Drawing from a decade of work with hundreds of twentysomething clients and students, THE DEFINING DECADE weaves the latest science of the twentysomething years with behind-closed-doors stories from twentysomethings themselves. The result is a provocative read that provides the tools necessary to make the most of your twenties, and shows us how work, relationships, personality, social networks, identity, and even the brain can change more during this decade than at any other time in adulthood- if we use the time wisely.
THE DEFINING DECADE is a smart, compassionate and constructive book about the years we cannot afford to miss.

本书是梁漱溟先生对山东乡村建设研究历届（自民国二十一年至二十五年）研究部同学，在朝会时讲话的笔录所集成。但只是笔录中的一部分而非全部。
本书非系统的学术讲演，而只是对同学之日常生活有所诏示启发，或自同学提出之问题，予以当下指点。故其内容包括有治学、修养及人生、社会、文化各方面之问题。多由阅历得来，语重心长，亲切隽永，足以发人深省，其有裨于青年者，至为深钜。兹不忍令其零佚，爰特编印成册，以供同好。
本书各篇之题目是后加的，朝话原无题目也。各篇先后之序，原宜以其年月日为准，唯已不易查明，今只有以其内容意义相连类者，而编次之，不复问其年月日先后。
本书内有一部分先曾陆续发表于《乡村建设》半月刊；其大部分则为黄省敏同学整理誊抄者。至某篇为某人所记，中因互相传抄，已无由记证。本书印行时，以先生事繁，复未经核阅。其有与先生愿意不符或小有出入者，当由笔记者与辑校者负责。