For more than 50 years, those engineering genetic material have pursued increasingly challenging targets. During that time, the tools and resources available to the genetic engineer have grown to encompass new extremes of both scale and precision（精准）, opening up new opportunities in genome engineering. Today, our capacity to generate larger assemblies of DNA is increasing at a rapid pace (with concomitant decreases in manufacturing cost). We are also witnessing potent demonstrations of the power of merging randomness and selection with engineering approaches targeting large numbers of specific sites within genomes. These developments promise genetic engineering with unprecedented levels of design originality and offer new avenues to expand both our understanding of the biological world and the diversity of applications for societal benefit.