This repository is a comprehensive, cross-implementation benchmark suite for R7RS Scheme. It provides a standardized harness that compiles and runs approximately 50 benchmarks (covering numerical, symbolic, I/O, GC, and meta-circular workloads) across more than 30 Scheme implementations, capturing execution times and correctness results. The suite exposes portability gaps, performance differences, and implementation bugs through its per-implementation prelude/postlude system, which adapts the common benchmark code to each Scheme's dialect. Results are output as CSV files and aggregated into summary tables and HTML charts (via graph-gmean.scm and graph.scm). While the benchmarks are well-structured and the harness is robust, many implementations are broken or incomplete, preludes are fragile workarounds, and the codebase shows age-related drift (e.g., deprecated APIs, hardcoded paths, and inputs too small for modern hardware).