The West Sussex town of Horsham, lying on the River Arun in the Weald, has given its name to the famous Horsham stone, a sandstone quarried locally and used since the Middle Ages for roof tiles and paving slabs. The area was known for its fossils in Victorian times and rival collectors of the day made important discoveries in and around Horsham, including three iguanodons. St Leonard's Forest on the edge of Horsham has also shaped the town, with iron smelting taking place there from Roman times, as well as charcoal and brick making.

In this book author Maggie Weir-Wilson reveals the hidden history of Horsham. Unsavoury tasks such as public hangings were banished to the common on the edge of town, along with leather tanning, while the town centre was the home of several weekly markets and annual fairs. A dragon was reported to be stalking the area in 1614 and is now a symbol of the town. The area was also the home of the young Catherine Howard, Henry VIII's fifth wife, as well as William Penn, the founder of Pennsylvania, and the radical poet Percy Bysshe Shelley. There are tales of ghastly crimes and punishment, the impact of wars at home and abroad, famous and notorious characters, writers and artists, poverty, industry, wealth and more in Secret Horsham as the author explores the little-known history of this West Sussex town.