California Rainbow Memories is a pictorial regimental history of the 2nd Battalion, 117th Engineer Regiment of the 42nd Infantry Division, published in 1919 shortly after the unit returned from France.

Synopsis

The book documents the wartime service of the California companies (D, E, and F) of the 117th Engineers, which were combined with South Carolina engineer units to form the engineer regiment of the Rainbow Division. It follows the battalion from mobilization through combat on the Western Front and homecoming. 

It covers:

• Organization of the California National Guard engineer companies.
• Training at Camp Mills, New York.
• The Atlantic crossing to France.
• Construction of roads, bridges, trenches, dugouts, and barbed-wire obstacles under enemy fire.
• Support of infantry and tank attacks.
• Service in the Champagne-Marne Offensive, Battle of Saint-Mihiel, Meuse–Argonne Offensive, and the final advance in Belgium during the Ypres-Lys operations. 

What makes it distinctive

Unlike a narrative memoir, California Rainbow Memories is primarily a commemorative pictorial history. It contains:

• Hundreds of photographs of officers and enlisted men.
• Images of camps, construction projects, and life in France.
• Informal snapshots taken by members of the battalion.
• Company rosters.
• Casualty and honors lists.
• Short essays describing the battalion's activities and accomplishments.