D.T. Suzuki was in his time a well known scholar on Buddhism, especially the Japanese Zen variety, and was later appointed a Professor of Buddhist Philosophy.
In 1948 Suzuki studied some sermons of Meister Eckhart and wrote this little book, pointing out what he felt were the close connections between the Meister's ideas and those of Zen Buddhism.
Having studied both Christian and Buddhist spiritual traditions myself quite closely, I think Suzuki has tried but failed to find common ground between these two great world religions.
Nowhere in Eckhart's sermons or tracts for example, does Eckhart conceive of God as Buddhist 'emptiness' or 'shunyata.' While it is true Eckhart felt God was One, and this One was above being itself, Eckhart also believed this One was a Trinity and contained a super-richness or overflowing of being, rather than a void which mysteriously and transcendently is the source of all other things. The Buddhist ideas which Suzuki refers to have far more in common with those of Oriental mysticism, such as the Tao of Lao Tzu or the Brahman of the Upanishads. Eckhart's idea is closer to Gregory of Nyssa or Dionysius, who saw God as infinite, perfectly One, incomprehensible but also a Trinity.
However many of Eckhart's ideas do have paralells in Buddhism, especially those on 'detachment', imageless contemplation (something shared with Evagrius Ponticus, a 4th century Eastern Christian monk) and the ground of the soul, which may be compared with the Buddhist notion of the inherent 'Buddha nature' shared by all beings. Yet, I think Eckhart is best considered what he really was, a Catholic mystic who saw himself as an Orthodox Christian through and through, rather than a Zen master in disguise.