Baby boomers, who were born between 1946 and 1964, are entering their retirement years. Since rates of self-employment rise with age, a disproportionate share of the self-employed is composed of middle aged or older workers. Some of these workers have been self-employed for much or all of their working lives while others have transitioned to self-employment later in their careers, often as a way of moving into retirement. Future predictions of baby boomers as a key catalyst for small business growth in the next decade and beyond have tended to neglect an important trend. The self-employment rate among those nearing retirement (defined as individuals aged 55-64) has dropped substantially in the past 20 years. This book addresses questions about this decline, and discusses the self-employment transitions among the older American workers with career jobs.