The journal Nature presents this online special feature on the recently sequenced Y chromosome. The Web site offers a number of free informative resources, including an account of the sequencing project as well as related scientific papers and letters published in the journal. An archive of Y chromosome-related articles are also available for registered users (no cost for registration). In all, this Web special offers an excellent resource for exploring the Y chromosome, formerly regarded as a "genetic wasteland" before sequencing research revealed that "we may have underestimated its powers."