What books should I have in my spiritual library? One’s personal ‘acquisitions policy’ is, to a great extent, a matter of interest and taste, but some guidance can be useful, particularly for those who are near the beginning of this journey. In what follows, I will recommend twenty-one books. The number twenty-one is, of course, simply a trope, a convention, a springboard into a world of reading that is entirely open-ended (full disclosure: I struggled to keep the list to twenty-one!). Furthermore, the books I suggest are merely examples of twenty-one types of material that one would do well to read. If the list is to be given a title, it is not ‘21 books you should have,’ but ‘examples of 21 kinds of book you should have.’ In any given area on the list, a better example might well be found, and if you find it, get it. I can hardly emphasize enough that the list below is limited and partial.