Short answers, pulled from the story.
Henry Edward Krehbiel was the chief music critic of The New York Tribune for more than forty years, from 1880 until his death in March 1923. He is considered part of the "Old Guard" group of New York critics who established a distinctly American school of music criticism, and a colleague described him at his death as "the leading musical critic of America."
After La mer's American debut in 1907, Krehbiel described it as "impressionistic daubs of colour smeared higgledy-piggledy on a tonal palette" and wrote that "the composer's ocean was a frog-pond." By 1922, after the work had entered the standard repertoire, he reversed course and called it "a poetic work in which Debussy has so wondrously caught the rhythms and colors of the seas."
Krehbiel's How to Listen to Music was first published in 1896 and remained in print until 1924. It was widely used as an instructional guide for the music-consuming public in the United States during the late nineteenth and early twentieth centuries.
Krehbiel published Afro-American Folksongs: A Study in Racial and National Music in 1914, which is recognized as the first music history book focused on African-American spirituals. His interest grew from hearing Black musicians perform at the Midway Plaisance during the World's Columbian Exposition, and he spent years collecting folk songs from Americans and immigrants of many backgrounds.
Krehbiel translated Alexander Wheelock Thayer's three-volume German-language biography of Beethoven for its first English publication in 1921. Thayer had died in 1897 without completing a planned fourth volume, so Krehbiel wrote one himself at 1,137 pages; it was published posthumously in 1925 as part of the second printing of his English translation.
Krehbiel was highly critical of both composers. He described Mahler as "a prophet of the ugly" and attacked Strauss for embracing hedonist themes he viewed as morally unserious. His criticism was rooted in his belief that great music should uplift the human spirit and intellect.