For the history of the canals, wikipedia[1] has a pretty good page. The Canal and River Trust (CRT) is the current authority for much of the canal system in England and Wales, and they have a site[2] with plenty of little articles on individual little bits and bobs.
If you're after more of a modern angle - i.e., stories and insights from people that live on them (or just use them) today, there are many blogs from boaters, but I tend to not read them unles I come across a particular post addressing something relevant to me (usually repairs...). There are also tons of vlogs and youtube channels where people document their journeys which other people in the comments have mentioned, and even TV shows! I highly recommend Canal Boat Diaries by Robbie Cumming, though outside the UK I'm not sure where it can be found. He also has a youtube channel [3] which is less highly polished and a bit more 'real'.
