The purpose of the invitation is to highlight the situation of Dawit Isaak and it will be sent via Sweden's ambassador to Eritrea, the Swedish consulate in Asmara and Eritrea's embassy in Stockholm.
In addition to the Book Fair, the sender is also the Swedish Writers 'Union, the Journalists' Association, the Swedish PEN, Reporters Without Borders and the Expressen.
Journalist Dawit Isaak has been jailed in Eritrea for 18 years without trial.
The Book Fair, which will be held on September 26-29, will this year install an empty chair "as a symbol of deprived freedom" reserved for Dawit Isaak "until the day he can come to the Book Fair, or voluntarily choose not to participate".
The chair will be next to the book publisher Gui Minhai's imprisoned book in China. Like Isaak, Minhai is a Swedish citizen.
"Through the official invitation to Dawit Isaak and that we set up a chair for him as well, we want to manifest and emphasize the importance of continuing to talk about the situation in both Eritrea and China," says Frida Edman, responsible for the Book Fair.