ADAM is a fast and scalable genome analysis tool that uses Parquet, a columnar file format, to limit I/O to only needed data. Parquet files compress well and are smaller than equivalent BAM files without data loss. ADAM leverages three layers of parallelism in Parquet and uses Spark for distributed computation and data locality management. The tool can transform SAM/BAM files to the ADAM format, run analysis like flagstat on data, and extract k-mers from sequences.