Mid-1800s: Transcendentalism, which borrows some elements of Eastern philosophies and religions, takes hold in Massachusetts and influences many American intellectuals and writers.

Today: Yoga is increasingly popular throughout the United States. Yoga, the Sanskrit word for "union," is a philosophy that was first systematized by the Indian sage Patanjali. The various schools of yoga taught today have some things in common with transcendentalism, such as the beliefs that each individual soul is directly linked to God and that truth is everywhere present in creation and can be experienced intuitively, rather than rationally. While millions of Americans practice only one element of yoga-its regimen of physical postures and exercises-a growing number are adopting the broader philosophy and its more mystical practices, such as meditation.

Mid-1800s: As the Industrial Revolution brings more efficient production of goods-which, in turn, makes goods more abundant and more...