Although Masefield had grand ideas for his book on the Somme, when he returned to England to write the book, he was denied access to the official records, and therefore, what was to be his preface to the book was in fact published as The Old Front Line, mostly a description of the geography of the Somme area where the battle was fought.

In 1918, Masefield again returned to America on his second lecture tour, organized by British officials with a view of using Masefield to further Britain's interests there. By this time, the US had strongly and unequivocally thrown their support behind the European Allies, and in fact had sent troops to fight with Britain. Masefield spent a good deal of his time in the US speaking and lecturing to the American soldiers who were awaiting the call to be sent to Europe. These speaking engagements were very successful for Masefield, and on one occasion, a battalion of all Black soldiers danced and sang for Masefield after his talk to them.