Alan Alda visits the research labs and testing tracks of the Big Three auto makers to find out what people will be driving 10-20 years from now. Fuel efficiency and alternative fuels are the future, and Alda test-drives a gasoline-electric hybrid that's already on the road, as well as several hydrogen-fueled cars still in development. The search for a quiet, fast, safe, exciting and non-polluting fuel-cell car takes Alda from Germany to California to Iceland, which is attempting to become the first nation to entirely replace imported petroleum with domestically produced hydrogen.

Alan Alda investigates how people create memories -- and how as they age, memories become slippery and elusive, sometimes vanishing forever. He visits two men who live entirely in the present or the distant past, unable to recall events that happened even a few minutes ago. Viewers peer inside Alda's own brain and find out what's at work as he memorizes names and faces. Alda discovers how ice water can boost memory (no, not drinking it) and how easy it is to have a false memory implanted. He also meets a volunteer in an experimental treatment for Alzheimer's disease, gets the latest on the search for an Alzheimer's vaccine and joins a group of baby boomers who are learning how to keep their brains young and their memories intact.

Alan Alda joins some of the world's leading astronomers as they wrestle with the startling implications of their latest discoveries: that everything we can see, from the world around us to the most distant galaxies, is only a tiny fraction of the entire cosmos. Most of what's out there is dark -- either dark matter or dark energy. And our universe is perhaps only one in an infinity of universes.

Alaska is warming up. It's now a few degrees warmer than it was a century and a half ago, and the trend seems to be accelerating. Already the landscape is changing dramatically -- permafrost is thawing, glaciers are melting, forests are succumbing to drought and insect attack. Alan Alda meets Alaskan scientists who are working to find out if these are the first signs of global warming and what the future may hold.

We discover the "you" inside your head - the part of your mind, sitting right behind your forehead that decides what you do every waking second of the day. We reconstruct a 150-year-old accident that caused a railroad worker named Phineas Gage to lose his sense of self; see children's reasoning powers gradually come on line; and scan Alan Alda's brain as he struggles to make decisions while feeling cheated.

Join James Lipton as he revisits some of the most hilarious guests in the past 10 years. In this segment: Alan Alda.

Alan Alda talks about growing up in the wings of burlesque shows while his father pursued his career as a tit-singer.

Tom Brook interviews Alan Alda.

Alan Alda Discusses His Favorite "m*a*s*h" Episode

Behind the scenes with actor Alan Alda.