He attended Russell Military Institute and Hopkins Grammar School in New Haven, Connecticut, reclaiming the education he left to become a soldier.

[4] In 1904 he set up a temporary residence in Des Moines, Iowa, and dedicated himself to working in isolation on the Compendium, compiling his collection of around 10 million names and dates, for almost five intense years.

He began to research using official records in various state capitals, and continued speaking to ex-soldiers and high-standing officers, such as General Sherman, who expressed interest in a comprehensive compendium and welcomed its future publication.

He made seven revisions, each taking around seven months, as he sifted through piles of paperwork and notes, to produce an accurate account of the Union army.

Published on February 15, 1909, by "The Dyer Publishing Company", through which he personally funded, wrote and promoted his work, printed by Torch Press of Cedar Rapids, Iowa, a total of 4,500 copies of the Compendium were issued in a single-volume edition, measuring 9 by 12 inches (imperial octavo), spanning 1,796 pages, and consisting of three parts:[1] Part II also contains 90 photographs of Union soldiers and officers, maps and drawings of uniforms and battles from the civil war, but also includes reproductions of Dyer's 1863 recruitment medical form, and several personal letters.

[5][1] The Compendium was well-received by civil war veterans and historians alike, who praised both its accuracy and value, as well as its thoroughness when compared to official military records.

He was buried at Mount Hope Cemetery, Boston, Massachusetts, in the GAR New Veterans lot on Webster Avenue, in an unmarked grave (no.