Mutant libraries allow identification of gene functions through forward genetic screens. A stably maintained mapped library can also provide mutants for reverse genetic characterizations of candidate genes. In the past several decades, methods used for generation, maintenance, mapping, and screening of mutant libraries in Chlamydomonas have greatly advanced. In this chapter, we summarize these technical advances and introduce how the newly available Chlamydomonas Library Project library has become a community resource. In addition, we provide perspectives on how recently developed sequencing and CRISPR technologies enable alternative strategies for mutant library generation and screening in Chlamydomonas.