The first episode: 'Fixing the Shadows' discusses the advent of photography and Daguerre's and Fox-Talbot's successes in preserving an image in 1839. It was interesting to see how the purpose of photography changed from formal studio portraits to informal snapshots mainly due to increased accessibility (and lower processing costs) provided by Eastman's Kodak cameras.
I was particularly struck by the complex set-ups required by Muybridge compared with the spontaneity of Lartigue's stop-motion photography.
The third episode: 'Right time, right place' is mainly about the decisive moment, and of course the work of Henri Cartier-Bresson. I'm not entirely convinced by some of the interpretations of his work, as I think there was a certain amount of luck involved - I believe this is true of all reportage-style photography as you cannot control every aspect of the composition.
The sixth and final episode: 'Snap Judgements' discusses photo manipulation. I was amused to learn about Camille Silvy who added elements like clouds and leaves on trees to an image as far back as 1858! It got me thinking that there is a good proportion of 'manipulation' in the vast majority of images we see. Isn't the use of artificial lighting and backdrops a form of manipulation? The use of fisheye, macro and zoom lenses can give a warped perspective of reality at times too.
Eureka! We have come full circle, right back to the purpose of a photograph.