This is a damn good book that sits perfectly alongside RRTCM and is just as easy to get your head around all the effects as they are explained in the book. There are very few illustrations but frankly there is not really much that you cannot pick up simply from the descriptions.
Personally, I don't really follow the Nikola system but something like this is completely down to your own personal choice and what fits the way your brain works.
Derren Brown covers some of this mnemonic stuff in Trick of the Mind but if you want to look into this kind of thing a little deeper without getting bogged down in all sorts of jargon, head over to Tony Buzans "Use Your Memory" and "Master Your Memory" books.
For those who have not come across it before, I would urge you to head along to :
http://www.thelearnedpig.com.pa
As this site has the Encyclopedia in PDF format for your reading pleasure ABSOLUTELY FREE!
Yes...
free.
The Encyclopedia or Card Tricks is in my mind an absolute must for anyones library. An unsung classic.