For all of its reach, Amazon, the company founded by Jeff Bezos in 1995 as an online bookstore, is still remarkably invisible. It makes it easy not to notice how powerful and wide-ranging it has become. But behind the packages on the doorstep and the inviting interface, Amazon has quietly positioned itself at the center of a growing share of our daily activities and transactions, extending its tentacles across our economy, and with it, our lives.