In this post in the Bill & Melinda Gates Foundation’s “Impatient Optimists” blog, co-chair Bill Gates discusses the foundation’s Reinvent the Toilet Fair, held this week in Seattle, which “brought together about 200 grantees, partners, and others who are passionate about creating safe, effective, and inexpensive sanitation services for people without access to flush toilets.” “The flush toilets we use in the wealthy world are irrelevant, impractical and impossible for 40 percent of the global population,” Gates writes, noting, “Worldwide, there are 2.5 billion people without access to safe sanitation — including one billion people who still defecate out in the open and more than one billion others who must use pit latrines” (8/14). A related post in the blog offers a behind-the-scenes look at how the Gates Foundation campus was transformed for the toilet fair (8/14).