The Spruce Gall Aphid (Adelges Abietis Linnaeus) in Southern Michigan by Bill Howard Wilford is a comprehensive study published by the University of Michigan Press in 1937. This work, part of the University of Michigan's School of Forestry and Conservation Circular series, explores the life history, gall formation, damage, and control methods of the spruce gall aphid, an insect that poses a significant threat to ornamental Norway and white spruce trees in the region. The research, conducted between 1929 and 1933, primarily at the University of Michigan’s Saginaw Forest, includes detailed observations on the aphid's taxonomy and complex life cycle. It examines how the aphid spreads and discusses possible mechanical and chemical control measures. The study also highlights the economic impact of the gall aphid, noting its aesthetic damage to spruce trees rather than severe growth reduction. The control methods suggested aim to manage and mitigate this pest's effects, making this publication essential for foresters, horticulturists, and conservationists handling spruces in similar environments.