General question about fonts

Hi,

I have been looking in Mac books and searching around the web for general tutorials about Mac fonts and I haven't been able to find what I'm looking for...

What I would like is a very basic tutorial on what Mac fonts are what.

For instance...there are two types of font that have the extension: ".otf", but some of them have an icon that looks like a piece of paper with a FontBook symbol on it (and under "Kind" says "OpenType font") & some of them have an icon that just looks like a slanted "O" (and says "TrueType font" under type). What is the difference? --Are both of them Mac types or is one a Windows type?

And what type of font is a "Font Suitcase" font? It just says that under type---w/ no extension, but I thought they were also TrueType fonts. Mac TrueType as opposed to Windows TrueType that is...(Windows TrueType have the extension ".ttf"). I believe it is OK to use Windows TrueType on OSX also, but I'm not sure.

Anyways...if anyone can steer me to a good tutorial that tells about that sort of thing (or can just answer some or all of the specific questions I asked)...I would really appreciate it a lot. Thanks very much!