Metabolic engineering has emerged as a promising strategy for the production of therapeutically important natural products and their analogs. However, the construction and manipulation of pathways of biosynthetic genes poses a key bottleneck to efforts to engineer cells for the production of complex natural products and their derivatives, and a new generation of transformative technologies will be needed to overcome this barrier. Towards this end, we have developed Reiterative Recombination as a strategy for the efficient in vivo assembly of multi-gene DNA constructs. Here we propose to develop our technology for metabolic engineering applications by challenging it in the context of optimizing terpenoid yields, specifically for taxol intermediates, in yeast. If successful, this research will make the construction of libraries of natural product biosynthetic pathways a routine, affordable, and highly efficient process that can be carried out by the non-expert without any specialized equipment.