Discworld is a comic fantasy book series written by the British author Terry Pratchett. 40 Discworld books have been published, the most recent being Raising Steam. The books are set on the fictional Discworld, a flat disc balanced on the backs of four elephants which, in turn, stand on the back of a giant turtle, Great A'Tuin. The books frequently parody, or take inspiration from, J. R. R. Tolkien, Robert E. Howard, H. P. Lovecraft and William Shakespeare, as well as mythology, folklore and fairy tales, using them for satirical parallels with current cultural, political and scientific issues.
The series has received additional interest because the author was diagnosed with early-onset Alzheimer's disease in 2007. Despite this fact Pratchett has continued to publish books in and out of the series. Pratchett is currently the second most-read writer in the UK and seventh most-read non-US author in the US. Many of the Discworld books can be grouped together into story arcs, each of which consist of a different set of characters and events. Below I list the chronological order of the series by story arc. The newest story arc is Moist von Lipwig (the name of the main character) and the third book in that arc, Raising Steam, was recently published. Pick up the first book in any story arc and see if you like it! I personally started with Going Postal, the first Moist von Lipwig novel; it's a good introduction to the series. And of course, the first book published in the series, The Color of Magic, is a good introduction as well.
Rincewind
The Color of Magic, The Light Fantastic, Sourcery, Eric, Interesting Times, The Last Continent
Death
Mort, Reaper Man, Soul Music, Hogfather, Thief of Time
Witches
Equal Rites, Wyrd Sisters, Witches Abroad, Lords and Ladies, Maskerade, Carpe Jugulum
City Watch
Guards! Guards!, Men at Arms, Feet of Clay, Jingo, The Fifth Elephant, Night Watch, Thud!, Snuff
Wizards
Equal Rites, Wyrd Sisters, Witches Abroad, Lords and Ladies, Maskerade, Carpe Jugulum, A Hat Full of Sky
Tiffany Aching
The Wee Free Men, A Hat Full of Sky, Wintersmith, I Shall Wear Midnight
Moist von Lipwig
Going Postal, Making Money, Raising Steam
Individual Stories
Pyramids, Moving Pictures, Small Gods, The Truth, Monstrous Regiment, Unseen Academicals
Note: The library does not own five books in the series, Hogfather, Sourcery, Maskerade, Feet of Clay, and The Last Hero. These can be requested through the Inter-Library Loan department for a $1 fee.