This programme covered the initial development both of writing itself, and of the alphabetic system we use today. He went and looked at (and described to us) examples of early cuneiform writing, Egyptian hieroglyphs and Chinese oracle bones, which are three of the four independent inventions of writing. It's interesting that something so fundamental to modern civilisation was invented so few times - as well as the three I listed there's also an independent development on the American continent, but all other writing systems were developed from other systems or directly inspired by other systems.
(It's actually a little controversial to say that Egyptian writing was developed independently like I did in the preceding paragraph - it may've been inspired by cuneiform, however the earliest known Egyptian writing is getting to be early enough that it's more likely to be independent. Also J's been reading a book about the development of writing, and it also makes the point that the Egyptian and Mesopotamian writing systems developed for different reasons - Mesopotamian writing was proto-book keeping, Egyptian writing had religious significance. So probably independent origin.)
I actually found the Chinese stuff the most interesting as it was completely new to me - in ancient China (in the Shang Dynasty) the rulers read oracles in the pattern of cracks that you get by using a hot poker on ox shoulder bones. These oracles were then recorded on the bones by scribes in the earliest known forms of modern Chinese characters, which makes the Chinese system the longest consecutively used modern writing system.
The programme also name checked Linear A (undeciphered) and Linear B (a syllabic system that was an early way to write Greek), and then moved on to the development of our more familiar alphabet. It made the point that the Greek alphabet was the first to write down vowels - previous alphabetic systems were for Semitic languages and due to the way those languages are structured the consonant sequences are less ambiguous (as I understand it). So to a native speaker it's a lot more obvious in context what a word is than it would be in English (or presumably Greek).