Prosperity spreads, technology progresses, poverty declines, disease retreats, fecundity falls, happiness increases, violence atrophies, freedom grows, knowledge flourishes, the environment improves and wilderness expands.Ridley backs up this statement with many statistics showing the progress of technology, health, lifespan, falling poverty rates, increased productivity in agriculture (including requiring less land than ever before to feed growing populations), and much more.
I haven't read his book yet, but look forward to doing so soon. Count me firmly in Ridley's camp as a believer that we have much to be happy about and many reasons for believing that the future is looking bright.
Here is a review of The Rational Optimist by John Tierney in The New York Times and a blog to go along with the book.
To help illustrate Ridley's point, here is a graph and associated research showing how much worldwide poverty has declined since 1970. (The graph is adjusted for 2000 dollars.) It is not just decreasing as a percentage of the world's population, but also in absolute numbers as well.