There’s an awfully good reason that the world’s top executives, entrepreneurs, and financiers gather in Aspen in July—and it’s not just the gorgeous weather. At our annual Fortune Brainstorm Tech, ideas sprout like wildflowers in a meadow. Ahead of this year’s summit—which is July 17 to 19 and by invitation only, though you can watch most sessions at Fortune.com—here’s a look at some of the luminaries who have graced the Brainstorm stage over the years.