Dear colleagues, Fluids are transient, but the signals they leave in metamorphic rocks can endure. We are pleased to invite contributions to a Special Issue of the *Journal of Metamorphic Geology *entitled: “*Signals of Fluid–rock Interaction in Subduction Systems: Petrological and Geochemical Perspectives*” Subduction-zone fluids link metamorphic reactions with mass transfer, volatile recycling, arc magmatism, and seismic processes. Exhumed metamorphic rocks provide our only direct samples of materials from the subduction interface and preserve valuable records of fluid and melt–rock interaction during burial and exhumation. This Special Issue aims to bring together studies that use these records to illuminate the sources, pathways, timing, scales, and consequences of fluid-mediated processes in subduction systems. We welcome contributions based on field observations, petrology, geochemistry, geochronology, experiments, and numerical modeling. Studies integrating multiple approaches or linking the metamorphic rock record with observations from active subduction zones are particularly encouraged. Submission deadline: *1 September 2027* Further information is available here: https://onlinelibrary.wiley.com/page/journal/15251314/call-for-papers/si-2026-000895 Guest Editors: Prof. Guibin Zhang (Peking University, China) Prof. Tatsuki Tsujimori (Tohoku University, Japan) Prof. Sarah Penniston-Dorland (University of Maryland, USA) *If your rocks have a fluid story to tell, we hope you will consider sharing it in this Special Issue. * Please also feel free to circulate this announcement among interested colleagues. Best regards Guibin, Tatsuki, and Sarah -- **************************************** Sarah Penniston-Dorland (she/her/hers) Professor and Chair Department of Geological, Environmental, and Planetary Sciences University of Maryland College Park, MD 20742 (301) 405-6239 sarahpd@umd.edu sarahpd23@gmail.com http://www.geol.umd.edu/~sarahpd/ ***************************************