Volume 10 of the Revolutionary War Series opens with Washington headquartered at the Continental army's encampment at Middlebrook, New Jersey, about seven miles northeast of New Brunswick, the location of the main British force under General William Howe. From this strategic vantage point in the Watchung Mountains, Washington could survey the country between Perth Amboy and New Brunswick while keeping an eye on the road to Philadelphia. Here he weighed contradictory intelligence reports. "The views of the Enemy," surmised Washington, "must be to give a severe blow to this Army and to get possession of Philada. Both are objects of importance; but the former of far the greatest—while we have a respectable force in the field, every acquisition of territory they may make will be precarious and perhaps burthensome." Washington also considered the possibility that Howe might attempt torendezvous his army with General Burgoyne's, thought to be en route fromQuebec to Albany by way of Lake Champlain and the Hudson River.

For his part, Howe, whose army outnumbered the Americans by a margin of more than two to one, hoped to lure Washington away from his defensive positions and force a general engagement. When a series of British maneuvers in late June failed to bring on the desired fight, Howe evacuated his army from New Jersey to Staten Island, leaving Washington completely in the dark as to the enemy's next move and keenly aware of "the great advantage they derive from their navy." Although Howe had abandoned the idea of attacking the main Continental army, from his new disposition the British commander easily could join with Burgoyne via the Hudson, move upon Philadelphia by way of the Delaware River or the Chesapeake Bay, sail farther south into Virginia or to Charleston, South Carolina, or sail northward and invade one of the New England states.

Washington's repositioned his army back at its old camp at Morristown, where it could better assist the American troops at Peekskill, New York, if Howe moved up the Hudson and yet still interfere with any British designs upon Philadelphia. Although surveillance reports revealed that the British were preparing for "a longer Voyage than up the North River," the British capture of Ticonderoga, New York, convinced Washington that Howe would take the northern route, and he swiftly marched the Continental army into New York state, where it remained until it became clear that the British fleet had gone out to sea. Washington then returned to New Jersey, where he made preparations for the defense of Philadelphia, but with several critical weeks of the summer campaign already passed, he confessed his puzzlement at his foe's decision to sail south.