In his article "Summing Up Sinatra," {Style, Dec. 26}, Geoffrey Himes noted that Frank Sinatra's "career divides neatly into three parts, each section connected to a different recording company."

But Himes omitted one period, perhaps the most profound, in Sinatra's climb to the rank as the country's top singer -- the formative years he spent as the male vocalist with Tommy Dorsey on the RCA Victor label, January of 1940 to September of 1942.

Sinatra cut more than 80 sides, many of which reached the top of the charts, including "I'll Never Smile Again," "This Love of Mine," "Blue Skies," "Whisperin," "The One I Love" and "Stardust." In 1941 he was voted the nation's top singer in Down Beat's prestigious poll. He beat out Bing Crosby and stayed on top for nearly a half-dozen years.

It was during his Dorsey years that Sinatra recognized the importance of phrasing, pacing and vocal dynamics. He developed the Sinatra style -- the occasional slurred notes and smooth, clear phrasing with not a sound of breathing -- thanks largely to his observing the trombone techniques of Dorsey. Sinatra became "Frankie" during those wonderful years and, of course, accrued a large following of devoted fans, I among them.

It would be correct to note, therefore, that Sinatra's career divides neatly into four parts -- the Tommy Dorsey, Columbia, Capitol and Reprise years. Although I favor the first two, because they conjure up the days of my youth as well as his, I'll take them all. Sinatra has proved that he is the greatest and grandest entertainer of the 20th century. May he live to be 400. -- Gary G. Beylickjian