Fortune's Most Powerful Women Summit Highlights: Arianna, Meredith Whitney, Melinda Gates (VIDEO)

Here on Postcards, you'll find a trove of video segments from last week's Fortune's Most Powerful Women Summit. Click here to watch a riveting take on the fall of Lehman Brothers by Barbara Byrne, a vice chairman who spent 28 years at the now-bankrupt firm. Today, since Barclays bought Lehman's North American core, Byrne is a vice chairman at Barclays Capital (BCS).

We also just posted the first of several highlights of my Summit interview with Melinda Gates, the lesser-known half of the world's most generous philanthropic couple. As I noted in a Fortune cover story on Melinda -- her first profile, which appeared in January -- she and Bill will almost certainly give away more than $100 billion in their lifetimes. Already they've disbursed more money than the Rockefeller Foundation since its founding nearly a century ago. And now, with their pal Warren Buffett's fortune in their fold, they're just getting started. Click here to see Melinda Gates talking with me about how to fix U.S. education.

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