“A Cinder Block Falling on Concrete” consists of sounds and stories from Lawrence Abu Hamdan’s Earwitness Inventory, a personal library of sound effects related to the testimony of earwitnesses in criminal investigations. The objects in Earwitness Inventory are derived from interviews that Abu Hamdan has conducted with earwitnesses, as part of his work as a “private ear,” as well as transcripts from trials across the globe. (Multiple entries concern the reconstruction of Syria’s Saydnaya prison and the experiences of detainees, which Abu Hamdan undertook with the London-based research agency Forensic Architecture and Amnesty International from 2015 to 2017.) The library is a means of considering how people remember (or misremember) sounds, and reveals the difficulty of describing such memories when precision is paramount. Earwitness Inventory has been presented as an installation, including ninety-five sourced and custom-designed objects/instruments along with animated text, in exhibitions at Witte de With Center for Contemporary Art (Rotterdam), Chisenhale Gallery (London), Contemporary Art Museum St. Louis, and the Institute of Modern Art (Brisbane).