The late Carl Dreher, a radio engineer drawn into Sarnoff's orbit in 1917, delivers himself of some opinions on the hard-driving visionary who built RCA, and fills in the background of his business deals--without producing anything close to a coherent biography. For that, one has to look still to Eugene Lyons' David Sarnoff and other repositories of the legends Dreher loves to debunk--most notably the young Sarnoff's feat in picking up the Titanic signals and monitoring rescue operations. ""He kept at his key,"" history has it. Not so Dreher: ""The fact is that Sarnoff was not on watch. . . . Even if he had been on watch, he could not possibly have heard signals from the Titanic. . . . Of course, as soon as he got the news, Sarnoff hurried to the station and began his vigil."" Then he took down the names of survivors transmitted by the rescue ship, a service to distraught friends and relatives and also ""an opportunity to make himself conspicuous and rise into the ranks of management."" On the other hand (and, this time, as an eyewitness), Dreher reports a visitation by the 31-year-old to choose between two competing radio recorders: ""His questions were based on engineering insight and had logical coherence and a crushing cumulative effect. It was an early application of what we now call systems engineering, coupled with managerial ability of a high order and almost terrifying determination."" So it goes, con and pro, with illuminating attention to the great Sarnoff coups from his 1916 memo envisioning radio as a ""household utility"" on the entertainment lines of the piano or phonograph to his push for compatible-color TV. But the account rambles, breaks, repeats--and generally seems not to have been whipped into shape for any readers other than researchers as determined as Sarnoff himself.