Ghost of the Shadow Market is a great addition to the Shadowhunter Chronicles. I loved the way the stories come together.
There is 10 Short Stories and the stories are from the year 1901 until the year 2013. Through the all 10 the stories we follow the life of Brother Zachariah/Jem Carstairs and everything that happened to him before and after the Dark War. Tessa Gray makes an appearance throughout the stories and she has a few surprises. We come across a few other characters like the Lightwoods, Herondales, Blackthorns and many more.
In the book you will get the chance to read about the background of a few characters in the previous books.
We learn more about the Shadow Markets in different cities.
I would recommend that you read all the previous Shadowhunter Book Series, The Mortal Instruments; The Infernal Devices; The Bane Chronicles; Tales from the Shadowhunter Academy and the Dark Artifices, before reading the Ghost of the Shadow Market.