This is where it all began. The first two books are written in quite a different style, and it’s not for everyone. However for those that stick it out you will uncover a highly satirical version of London from both the eyes of a tourist and a local.
A parody of magic and monsters often based around fairy tales. The stories feature a tight cast of witches that operate in and around a sleep country town nestled in the Ramtop Mountains. Granny Weatherwax, one of the witches, is one of the most well-loved characters within the series.
Great whodunit/conspiracy stories that feature the Ankh-Morpork City Watch, the city's police force, Lord Vetinari, the cities patrician, and a variety of cameos from the other arcs. This story arc is arguably one of the most popular, largely due to the strong character development.
Pretty much what it says on the tin. Each of these books brings a new technology to Ankh-Morpork which thereafter feature strongly in the following books. While other arcs focus on character development, these arcs pull Ankh-Morpork into the 19th century.