Abstract: Provided are compositions and kits comprising recombinant adeno-associated viruses (rAAVs) with tropisms showing increased specificity and efficiency of viral transduction in targeted cell-types, for e.g., the brain and the liver. Therapeutic and bio-medical research applications of the rAAVs are also described, including without limitation methods of discovering rAAVs using a multiplexed Cre recombination-based AAV targeted evolution (M-CREATE) method, and methods of treating various diseases and conditions by rAAV-mediated transgene therapy.