This protocol is for the preparation of genomic DNA (gDNA) libraries using enzymatic gDNA fragmentation with either the Twist Universal Adapter System or the Twist HT (High-Throughput) Universal Adapter System. The Twist Universal Adapter System and Twist HT Universal Adapter System improve the overall performance of any ‘T-A’ overhang ligation library preparation workflow for next-generation sequencing (NGS) applications. This manual details the steps for generating the amplified, indexed libraries needed for downstream target enrichment and sequencing on Illumina NGS systems. This library preparation protocol is optimized for use with Twist Target Enrichment Kits and should only be performed with reagents specified or their equivalents.