George Washington's Engineer

In January 1776, George Washington had a problem: the British army controlled the city of Boston. The colonial army needed to force the British to leave. But how?Washington had a solution: ask his engineer Rufus Putnam to solve the problem. They needed to take control of the high ground, Dorchester Heights, just south of Boston. They could place cannons there to bombard the British army. Cannons on Dorchester Heights meant the colonials needed to build walls to protect their soldiers.
But January in Massachusetts was so cold that the ground was frozen. No one could dig foundations for walls. Putnam needed an engineering miracle. Courage and engineering ingenuity are celebrated in this intriguing story of the role of engineering in the Revolutionary War.