How do you improvise? How can you learn the art of improvisation? By considering these two questions this thesis aspires to make a contribution towards a greater understanding of what the production of improvised music actually involves. The organ has long traditions of being used to play improvised music and is the main focus of this thesis. The study also includes three different recording projects presented on four CDs. These musical manifestations are intended to serve as demonstrations of working methods, references to this thesis but can also be seen as independent works of spontaneous music pieces. Thesis for the degree of Doctor of Philosophy in Musical Performance and Interpretation at the Academy of Music and Drama, Faculty of Fine, Applied and Performing Arts, University of Gothenburg. Including 4 music CDs. Denna avhandling är nummer 6 i ArtMonitor-serien.