what is mobile phone tools? and unlocking

I am new to this posting site for phones, and i just got a motorola e815. what will phone tools do???? please tell me. and do i unlock for any reason and what does that do? is all i need a usb cable cause i don't think my phone has a usb port. does that phone hacker bible do anything at all as mentioned on the first page. i honestly don't know any of this and don't know any of the benefits as well, any and all help would be greatly appreciated, as i am in the dark here.