From the introduction:
To Challenge Tomorrow is a new concept in role-playing games, a set of simple and easy to learn mechanics which can be adapted to any setting or background. We designed TCT because we saw a serious need for good mechanics which could be adapted into any campaign as a replacement for the kind of substandard rules which so often come with otherwise promising games. The TCT mechanics are designed to promote play with fully developed characters and detailed campaign background, with an emphasis on imagination and originality.
To Challenge Tomorrow Basic Rules v4.3 was distributed as "ShareText" - using the same basic idea as software ShareWare. The game file was free, but if used for more than 30 days the user was required to send payment to the publisher. More information is contained in the file itself, available for download below.