I struggled to find the correctly qualified name of a type in a dll I was trying to use, but found GetTypes() really useful in listing all available. In VB:
Dim t As Type() = assem.GetTypes()
Dim s As String = ""
For i As Integer = 0 To t.Length - 1
s = s & t(i).FullName & vbCrLf
Next i
MsgBox(s)