Probably you have tried occasionally to find something on the other side of the dream-boats. Getting started usually is a disaster - remember the “Getting Started”-chapters you ploughed through and you know what I mean. Leaving a dream-boat and clearing your mind takes much more time, some say several lifes. My own experience has taught me one thing: the original is better than the dummies they want to sell to you. The crucial criterion is clarity. That is true both in IT and in ZEN or equivalent disciplines. There is nothing wrapped in mystery in basic texts of mystical traditions like ZEN, Tibetan Tantric Buddhism (Dzogchen) or some parts of Christian Mystics - odd thing, isn’t it? Since I am not an expert for other traditions such as Sufi or Kabbala, I cannot judge these.
Some IT friends asked me to arrange a small bibliography with less well-known clear texts here and I hope that my limited time will allow me to complete it.