The Hundred-Year-Old Man Who Climbed Out the Window and Disappeared by Jonas Jonasson (2009) — Not set in Kiruna, but this wildly popular Swedish comic novel captures something essential about the Swedish character: phlegmatic, resourceful, and unimpressed by authority. An enjoyable way to get in the Swedish frame of mind before you go.
Sami: An Indigenous People in Sweden by the Sami Parliament of Sweden — A short, readable introduction to the Sámi people and their relationship with the land that Kiruna sits on. The reindeer herders, the joik music, the conflict with mining and development — the context makes visits to the area much richer.
The Ice Palace by Tarjei Vesaas (1963) — A Norwegian novel, not Swedish, but set in a landscape indistinguishable from the Swedish north: a frozen lake, a waterfall turned to ice, a child lost in winter. Spare and haunting, it captures the northern winter better than almost anything else in fiction.
The Sámi Peoples of the North by Neil Kent (2014) — A comprehensive history of the Sámi across Norway, Sweden, Finland, and Russia. Kent covers traditional life, the impact of colonisation, and the modern political situation. Heavier than the others but worthwhile if you want real depth.