Samevatting iv Sleutelwoorde iv 1.3. Noncommutative Banach function spaces 9 Chapter 2. Weighted Banach Function Spaces 2.1. A first definition of weighted non-commutative Banach function spaces 2.2. The map τ x 2.3. Weighted non-commutative decreasing rearrangements 2.4. Equivalence of weighted spaces Chapter 3. Weighted Orlicz Spaces 3.1. Young functions and Orlicz spaces 3.2. Equivalence of weighted Orlicz spaces 3.3. The Köthe dual of weighted noncommutative Orlicz spaces Chapter 4. Interpolation Spaces of Weighted Banach Function Spaces