Having read the works posthumously published, after the classic Returning to Silence, published shortly before Katagiri's death, this is the most clear and understandable of Katagiri's works I have read.
I much enjoyed this read and found it inspirational and educational as to Zen and, also, zazen as a way of life. I, likewise, appreciated that Zen is presented as inclusive of other wisdom paths other than Buddhism.
In fact, Katagiri informs us that we cannot know what Buddha Nature is, or Christianity, or nirvana, or heaven, or enlightenment, or anything we tend to glamorize spiritually, we can only experience life directly to know beyond our labeling. Even Buddha does not know who Buddha is, such is the nature of knowing beyond conceptual notions.
As to the paradoxical teachings in Zen, Katagiri acknowledges such. He, however, clarifies Zen itself is not paradoxical. In direct knowing, this one moment, there is only a simple knowing, or seeing, free of confusion, free of any apparent contradiction, all being in harmony.