Recent molecular techniques reveal inversions as common balanced rearrangements. Inversions flip genomic sequence orientation without quantitative loss. Most inversions are phenotypically silent unless breaking coding regions. Classical view of inversions causing subfertility is contradicted. Inversions play key role in human genome evolution. Improved methods enable genome-wide inversion detection. Inversions link to demographic history and genome architecture. Non-allelic homologous recombination forms inversions. Segmental duplications facilitate inversion events. Studies explore inversions in complex genetic disorders.