Extensive online help is available for Chimera; the User's Guide and Programmer's Guide are written in HTML and can be displayed using the web browser of choice.
The Help menu contains several choices. About Help opens this manual page. Context Help changes the cursor to a question mark and will bring up help about the next item clicked on with the mouse; when clicking on a tool, click on a region other than the top bar (since that will fail to bring up a help page). User's Guide opens the Chimera User's Guide. Check for Updates reports if the version being used is older than the latest version available on the web (requires internet connectivity). Feedback provides e-mail addresses for reporting problems or making suggestions. Citation Info describes how to cite Chimera usage. Registration... provides a form for registering as a Chimera user; registration is free and the information provided will only be used for announcing important bug fixes and reporting summary usage statistics to NIH. Finally, About UCSF Chimera shows copyright information and what version of Chimera is being used (like the command version).
To get help on a specific command, type
help commandin the Command Line.
for example,
help color
Many of the tools and interfaces have Help buttons that open their respective manual pages. Some tools and interfaces also supply balloon help, explanatory text that pops up when the cursor is left in certain positions. Balloon help is on by default, but can be turned off in the General preferences.