Continuing with this month's theme of understanding the Temple more fully, I have made a list of my favorite sources. As you can see the list has been broken up into two catagories. The first group is writings by Mormons and the other is not. Please be warned: all these books are heavy reading. The usual introductory recommended is not listed.
LATTER-DAY SAINT SOURCES FOR TEMPLE UNDERSTANDING:
My Father's House: Temple Worship and Symbolism in the New Testament
by Richard Neitzel Holzapfel
The Gate of Heaven by Matthew B. Brown
Temple and Cosmos by Hugh Nibley
The Sermon at the Temple and the Sermon on the Mount: A Latter-day Saint Approach by John Welch
The Lost Language of Symbolism by Alonzo Gaskill
NON-MORMON SOURCES FOR TEMPLE UNDERSTANDING:
The Great Angel by Margaret Barker
The Revelation of Jesus Christ: The Revelation of Jesus Christ: Which God Gave to Him to Show to His Servants What Must Soon Take Place (Revelation 1.1) by Margaret Barker
You can find more information about Margaret Barker at Thinly Veiled where there is a list of her works with excerpts.
The Hero with a Thousand Faces by Joseph Campbell
The Sacred and Profane: The Nature of Religion by Mircea Eliade
Images and Symbols by Mircea Eliade
More information can be found at
Resources for Understanding the History
and Symbolism of LDS Temples for a larger comprehensive list.