Tintin and Asterix were the two cartoon strip characters I loved as a kid. Both comic books age well - its enjoyable to read them again as an adult. On a recent trip to Montreal, I took cover from the rain and sat in a bookshop and read through "The Shooting Star" ; a slightly guilty hours pleasure. There's a short biography of Herge on Expatica, including a hint about a most intruiging unfinished work:

Herge passed away on 3 March 1983, leaving his last book, “Tintin and Alpha-Art” unfinished. The book was to delve into the world of modern art and sects.
Expatica - The Adventures of Herge