All the 108 Upanishads with the Sanskrit moolam transliterated in Malayalam with detailed description of each verse in Malayalam prose.
About the Authors
V. Balakrishnan and Dr. R. Leela Devi have about 312 books to their credit. A list can be seen <a href="http://www.scribd.com/doc/50599396/List-of-Books-by-V-Balakrishnan-and-R-Leela-Devi">here</a>.
They have extensively written about Hindu philosophy.
A brief sketch of V. Balakrishnan can be seen from <a href="http://en.wikipedia.org/wiki/V._Balakrishnan_(author)">here</a>. A brief sketch of R. Leela Devi can be seen from <a href="http://en.wikipedia.org/wiki/R._Leela_Devi">here</a>.