Andreas Willscher's four cycles of animal compositions, Insektarium (2004), Aquarium (2008), Vogelarium (2011) and Terrarium (2015), are the focus of this most recent recording by Jürgen Rieger. Born in 1955, Willscher is renowned for his contribution to German contemporary music, and the organ plays a huge role within his works.

The three-manual Oberlinger organ used in this recording can be found in the Protestant Parish Church of Dillenburg (Central Hesse). It was built in several phases, with the project beginning in 1990. The organ sits behind a historical case built by Florentinus Wang in 1719, making it a memorable visual feature within the old church. It is also know as one of the best-sounding organs in the Central Hesse region, attracting many visitors from near and far.