Within <HTML>, the document has two sections to it: <HEAD> and <BODY (Other atributes :: Discussed later.)>. <HEAD> is like the cover page of the document. Just as the cover page of a book contains information about the book (such as the title), the <HEAD> section contains information about the document. This information is communicated through the <TITLE> tag (which is required) and the <LINK (Other code, Discussed later.)> and <META (same story...)> tags.
The <head> tag is more for the browser (This time, I'll assume you know it is what you see the internet in.) than for the user. One mark of a good website is that it will include EVERY possible tag that the <head> tags allow. Then there is the <.head> tag. It tells the browser that the head section is over. Thats about it...