I have tried to take Crowley's book in small doses - it can be very overpowering, but there are many things in it that I can't get enough of. ( It's kind of like the first time I tired to read Grave's The White Goddess - I had no idea where the heck he was going and couldn't understand how he was gonna get there - now I am three quarters of the way through, reading, re-reading, and going over some parts just for the pleasure of it - and I plan to read it again and some of his other stuff once I finish this one.)
I have not yet gotten Duquette's book, but my Thoth chat group seems to think highly of it. Whenever I use my Thoth deck, and other Thoth style decks that may not have their own book, I have referred to Ziegler's Mirror of the Soul. It is concise, clear, gives meanings, affirmations, mediations (some of which have found their way into my meditation journal). I have used it so often it is falling apart - must get another.
Another good one - but chock full of information - is Arrien's Tarot Handbook. She gives permission to photocopy the pages she made up for logging daily cards, personal growth cards - a real help for me - I am in my second year of logging every card I pull for myself, keep the sheets in my journal, and review from time to time to see what cards keep coming up, what trends there are - a very wonderful visual aid.
Hope this helps.
Thea Lynx