On vacation I am reading the Issues, Etc. Book of the Month, "Luther's World of Thought" by Heinrich Bornkamm (translated by Martin H. Bertram). Anywho, there's a nice summary of Luther's life in the opening chapter, complete with many details I had not known or had forgotten. Not to mention many pertinent Luther quotes, like the one here from a chapter about, "The Hidden and the Revealed God":
God sends forth no magistrates or angels when He creates, fashions, or preserves something, but in all this is the peculiar work of His divine power. But if He is to create and preserve it, He must necessarily be present and create and preserve his creation both in its innermost and outermost particles, around it and about it, through and through, below and above, in front and behind, so that nothing can be present or within all creatures byt God Himself with His power.
His divine being can be entirely in all creatures and in each individually, deeper, more intimately, more present than the creature itself, and yet again be encompassed nowhere and by none, so that He, to be sure, encompasses all things and is in all things, but without having any creature in Him and without being encompassed by any. (Bornkamm pp. 53-54)
Read this quote carefully and you will see not an Oriental Mystic or a Christian Scientist or New Age Guru, but a thoroughly Christian (and, of course, Lutheran) understanding of God's "Omnipresence". Lots more could be said here - lots of connections to Luther's thinking about the Sacraments, the Incarnation etc... but I am not done with this excellent book yet either!