By modern standards, it's a lightweight and fairly minimal window manager. It is enormously configurable however, and can be made to look as simple or complex as you prefer. See our Themes page for some examples.
In 1987, Tom LeStrange wrote the TWM window manager, which was adopted by the X Consortium as the standard window manager in 1989. In 1992, Claude Lecommandeur added virtual workspaces inspired by HP's vuewm, and so CTWM was born. Over the following years, he made further changes himself, as well as integrating improvements from other people who had taken up using it.
In 2003, Claude retired from developing and maintaining CTWM, and passed control of the project to Richard Levitte <firstname.lastname@example.org>. He oversaw it until 2014, and then passed it on to Matthew Fuller <email@example.com>, the current maintainer.
CTWM had no official website for its first decade or so. Dan Lilliehorn maintained a site dedicated to CTWM between September 14 1999 and 2003. When Richard Levitte took over maintaining CTWM, he also took over Dan's page and made it the official CTWM website.
Through his tenure and future maintainers, it has remained so, though it has been updated and significantly reworked since that time.