Accessing calling application from a .dll

Question

I have a vb.net application that accesses a vb.net .dll file. That .dll file works fine and does what it needs to do. But what I am wondering, is it possible for that .dll to call methods on the main application directly? Right now I have the .dll accessing another .dll to do some logging and whatnot, but it would be much easier for me if the first .dll could do what it needed to do and then just call some methods on the application that called it. Is this possible?