The history is the first publication by the trustees and committee of Victoria County History Shropshire Ltd, a charity, and is a "short," or single-case study, shining the spotlight on the town.
The launch is at 11am at Wem Town Hall and is open to all, with copies of the book on sale.
Professor Richard Hoyle, who chairs the trustees, said: "Wem has proved to be even more fascinating that we envisaged. Our history of Wem will take its readers into all manner of previously unexplored corners of the town’s history.
"It sets a new standard for the writing of local history in the county."
The book reveals for the first time that Wem was a planted medieval castle town.
Among the "did you know?" facts are: It has been a market town for over 800 years; in 1642 the Parliamentarian garrison held off a Royalist attack; the "great fire" of 1677 destroyed many of the existing buildings in the town centre, a factor in its predominantly Georgian and Victorian appearance; Wem is the home of the modern sweet pea; the town's Norman castle can be found in a High Street back garden; a smart new suburb of Wem was called Islington and had a pub called The Angel; and Wem bridge was designed by Thomas Telford.
Written by Judith Everard, James Bowen, and Wendy Horton, this first "short" is intended to establish a model for the histories of other towns, villages and parishes in Shropshire.
The Victoria County History is the biggest publishing project in English local history which aims to write the history of every parish and town in England, but for years progress in Shropshire stuttered and stalled, before VCH Shropshire, a voluntary group, was established in 2015 to continue the work locally.
It became a charity in 2017. It is an independent organisation, but works to the standards of VCH nationally.
The Wem book is paperback, 174 pages, with 35 figures, and five maps. Price until December 31 is £14, and afterwards, £16. After the launch it will be available from good bookshops and by post from the VCH Shropshire website (www.vchshropshire.org).