This method describes the preparation of Illumina sequencing libraries with a 1/20 scale Nextera protocol. Typically, yeast or E. coli plasmid DNA is the input. Method derived from: Baym M, Kryazhimskiy S, Lieberman TD, Chung H, Desai MM, Kishony R (2015) Inexpensive Multiplexed Library Preparation for Megabase-Sized Genomes. PLoS ONE 10(5): e0128036. doi:10.1371/journal.pone.0128036