Can someone help me with a reference or a link of a tutorial on how and when to understand the use of dictionaries in excel VBA scripting? I have seen lots of Excel Gurus use the dictionaries and I have tried to understand this methodology and when to use them.
If possible to include a code with comments on each line so that I can understand the use of the dictionary.
Examples of the dictionary scripting are as follows:

CreateObject("System.Collections.SortedList")
CreateObject("VBScript.RegExp")

Or if you know of any Excel book that explained this in details, please let me know also.