Some of the audio quality is not optimal; we continue to improve our sound recording techniques.
You may listen to the recordings on the web using a standard player (e.g., Real Player, Windows Media Player, iTunes, etc.).
The .mp3 files may be downloaded to a portable listening device (e.g., iPod, etc.).
The .mp4 files are "enhanced podcasts," which include images accompanying the speech; they will play on iTunes or downloaded to a video iPod, only.
Video recordings link out to Columbia University's YouTube channel.