This book was first published in 1963 and rewritten in 1996 and published again under the same title. See the information in the book explaining this:
Year of the Tiger was first published by Abeland Shulman in 1963 under the authorship of Martin Fallon. The book went out of print very shortly after its first publication, was never reprinted and never appeared in paperback.
The author was in fact Jack Higgins. Martin Fallon was one of the pseudonyms he used during his early writing days. In 1994, it seemed to the author and his publishers that it was a pity to leave such a good story languishing on his shelves. So Jack Higgins has created an entirely new framework to the original book, added some scenes and made some changes throughout. We are delighted to be able to bring back Year of the Tiger for the pleasure of the vast majority of us all who never had a chance to read the original edition.

1962. The cold war heats up as the space race begins. And one scientist, living under house arrest in Chinese-controlled Tibet, holds the key to victory.
Paul Chavasse is inserted into Tibet on a desperate mission that may be the West's only hope of beating the Soviets to the moon. He must locate -and smuggle out- Dr. Karl Hoffner. But enemies are every where -from Chinese occupiers and distrustfull natives to Soviet agents shadowing their every move. Fighting for their lives, Chavasse and Hoffner must race across one hundred rugged miles to freedom, as the future of space travel -and the world- hangs in the balance...
First page of the book : In March 1959, after the failure of the revolt by the Tibetan People against their Chinese Masters, the Dalai Lama, with the help of the CIA and the British intelligence sources, escaped to India. A remarkable affair, and yet three years later the British masterminded an even more remarkable coup. It went something like this .....

With many thank to Bigblueben@aol.com who sorted out how the book was published twice:

Year of the Tiger. There really are two separate books with the same title. In 1963 he wrote Year of the Tiger and it was published only in hard cover. In 1996 he re-wrote some chapters and made some other changes and the publisher released it. I carry the title twice on my listings.