CHECKPOINT by Charles W. Thayer. 303 pp. Harper & Row. $4.95.
Like many another weanling career diplomat, Charles Thayer knew Berlin before the war. Afterward, as Foreign Service officer, unofficial State Department troubleshooter and finally, journalist, he often went back. Now he has written an international spy thriller. To no one's surprise, the book is about a man who served in prewar Berlin as a weanling career diplomat and then, as a journalist and State Department troubleshooter, gets called back to help out during a Berlin Wall crisis.
Checkpoint reeks of authenticity. Some of it is just that of a competent journalist rendering...