Hell... if you're at Hanks next month I'm less than two hours away... on the opposite side of the state
Ok... some have attempted to guide you away from Docc and even Bob Cassidy... I'll assume it's because they've either never studied either, or they don't have the maturity required for doing "the real work" as it were.
You asked about Docc and as I stated, Docc's stuff is far more Bizarre oriented than what I'd classify as Mentalism. He does have a neat video out for the billet novice entitled
FASTER THAN A SPEEDING BILLET available through Floraco (you may check with Stevens Magic in the States they used to carry it). Elliott's
SWITCHCRAFT is quite excellent especially considering how much "more" you get for the dollar ventured but if you are heading down billet alley you must study Cassidy, Allen Zingg, Millard Longman and the John Rigg's manuscripts on the Q&A.
I cover a lot of this in my treatise here at TM about becoming a Mentalist... it's a sticky post, just do a search. But be very careful about taking the advice of magicians on this topic...
you wouldn't ask a carpenter how to install the plumbing in your home, now would you? Either are considered skilled trades and part of the construction industry but they are obviously different... same with Magic vs. Mentalism, which brings me back to Bob Cassidy and his little essay on said topic in his book
THEORIES & METHODS FOR THE PRACTICAL PSYCHIC... said book containing some priceless points of view for those "new" to the Mentalism world... but then I tend to be old school, just like Bob, of course I'd agree with him
There's been a flood of books, tricks and theories published in the past decade by Magicians seeking to cash in on a trend cultivated by two street punks and a British cynic, each with the respective Tv spots and with the exception of Derren, NONE of them having any real background in mentalism to speak of... just material they were taught by real mentalists on their payrolls, most of which has so many holes in it a blind person can see them with their cane. When it comes to the wonderful realm of eBooks and Lulu type releases... well, what can I say, anyone can get published under such auspices, it does not mean they know what they are talking about or that they are in fact an "authority" let alone the voice of experience

Pardon, this is just an area of issue that gets me a bit choked up -- pisssssed!
The bottom line, as far as I'm concerned, is don't waste your money on materials that came for folks with little to no real world experience in the field you wish to learn about... not just magic or mentalism but ANY area that sparks your interests. Seek out and learn from the old timers be it via their books, videos or frequent long winded telephone chats.
I have a small handful of Old Guys I talk to regularly, most of them are people today's commercial ladder climbers have never heard of and on many levels, don't want to believe exist... far be it that there exist "inner circles" within this craft that would keep them out and unable to get their mitts on unpublished or carefully guarded secrets... BUT THERE ARE... sort of.
I don't want to go even further off topic with this issue, but I want you to see that LEARNING is an on-going endeavor and learning the subtle and nuance elements that make Mentalism (and even certain facets of magic) more "impossible" and "enchanting" demands that you not attempt to keep up with what everyone else is chasing and clamoring about; it means that you listen and RESPECT those that have been there and actually have and do, DO IT FOR REAL.
Please, if you never read another thing of Bob Cassidy's, get THEORIES & METHODS and study what he has to say about Mentalism v. Mental Magic and or Magic itself. Learn what he says and does with the Billet Read and see for yourself the power of belief vs. the stupidity of excuses and disclaimers. Discover how to run the hustle without being a charlatan and how to be a miracle maker without being sentenced to the negative stigma associated with magic and magicians.
Pardon my rambling but it's important to me that anyone new to this field get pointed in the right direction and even those that would attempt to detract from my point of view are, in certain instances, regurgitating the very things I told them a few short years ago, before their perspective got tainted by false success and the airs of being part of a good ole boys drinking club.