A former Swedish military intelligence organisation. It is an akronym for Informationsbyrån or Inhämtning Birger (after its head Birger Elmér).
The IB was set up by the Social Democratic Party (SAP), which has been in power in Sweden almost without interuption for 70 years now. The task of the IB was to spy on and register people with wiews to the left of SAP, to infiltrate left-wing organsitaions etc. People could get registered for parking their cars in the wrong places. People who had been registered were then opposed in all sorts of ways: they were denied jobs, promotions, they were kept from getting higher positions in trade unions etc. This was of course contrary to almost every applicable law, especially the one explicitly prohibiting the spying on and registering of people because of their political wiews.
In 1973 the journalists Peter Bratt and Jan Guillou exposed the activities of the IB in the magazine Folket i Bild/Kulturfront. One thinks there should be some serious legal consequences, and in a way there were. The two journalists were convicted of espionage. While Swedish press-freedom legislation made it impossible to prosecute them for their articles, it was argued that they had committed crimes in obtaining their story.