One of three children, Ottolengui was a son of Daniel Ottolengui and Helen Rosalie Rodrigues Ottolengui; he had a sister, Helen, and a brother, Lee. He was cousins with
Octavus Roy Cohen, who also wrote crime fiction. He was the editor of
Items of Interest: A Monthly Magazine of Dental Art, Science, and Literature for thirty-five years, which he continued to edit after retiring from dentistry; he compiled
Table Talks on Dentistry, drawing from articles in
Items of Interest. A dental pioneer, Ottolengui was one of the first to use
X-rays and was a specialist in
orthodontics and root canal therapy. He was also interested in
entomology,
taxidermy, and
photography. In addition to his work in dentistry, Ottolengui is remembered as an early exponent of detective fiction, with four novels and a short story collection published during the 1890s. The short story volume,
Final Proof, was recognized by Ellery Queen as one of ''Queen's Quorum
—the most important collections of detective short stories. Many years later a second series, Before the Fact'', originally published in 1901, was discovered and published in book form edited and introduced by detective fiction scholar
Douglas G. Greene. His wife, May C. Hall Ottolengui, died on 10 July 1936; he died at his New York residence the next year of a heart ailment and a stroke caused by a long illness. His sister died on 22 July 1938. ==Bibliography==