Whois  is a tool for retrieving the data about domains and IP addresses from the whois databases.
With it's help you can find all the info about an IP address, network or domain. In automatic mode it can recognize and search the databases for an IP address or domain (note that domain means "yourhost.com", not "www.yourhost.com"). You can also select the particular server and ask it whatever you want. Ask the server for HELP keyword to get the extended search rules.
For your convenience, whois highlights the data, that looks like information handle, so you can just click on it and repeat the query.

Default servers, that assumed to have the whois daemon and databases are ARIN, RIPE, APNIC and InterNic (Network Solutions). Info from that databases may be retrieved in automatic mode. Other databases require to be included in list (just use "more" selection).

All the data you can acquire from server may be saved to text file (button at right top). Whois's window is resizable and answer view may be customized (Options button).  Right-click on the window copies the selected data to the clipboard. Button "Data >" copies the clipboard contents to the question line.

Old queries are not erased and may be navigated through with the help of "forward" and "back" buttons.