This atlas provides ultrastructural morphological images of human spermatozoa. Sperm morphology plays an essential role in sperm-oocyte interactions and early embryonic development, and human sperm ultrastructural morphology offers a valuable reference tool for assessing certain etiologies of male infertility and reproductive failure. However, the ultrastructural morphology of human sperm has not been systematically evaluated or thoroughly described in the literature. Using 470 original and unpublished images, the book shows various ultrastructural morphological phenotypes; defects of the sperm head, neck, middle piece, principal piece, and terminal piece; as well as artefacts of sperm ultrastructural morphology and phenomena related to inadequate preparation, demonstrating many sperm phenotypes and surface structural appearances for the first time. As such, it helps researchers and practitioners in andrology, reproductive medicine, and reproductive pathology gain a better understanding of human sperm ultrastructural morphology.