Martin Brennan trained in visual communication at Pratt Institute. He has travelled extensively in Mexico where his interests in prehistoric rock inscriptions, ritual, and traditional art developed. Spending more than a decade in Ireland engaged in active research on megalithic art, he tapped into some of the earliest methods of recording numbers and the fundamental beginnings of writing, and reported these startling discoveries in his critically acclaimed The Stars and Stones, later reissued as The Stones of Time. He is also the author of Hidden Maya. He lives and teaches in Boulder, Colorado.