Radio reporting's ""finest moment""--Edward R. Murrow On a rooftop in London during the blitz--is also the highlight of this otherwise often cumbersome recapitulation of on-the-spot broadcasting from the early 1920's to the end of World War II (the ""golden age""), with a glance back at the pioneers and a probe of the present. The bulkiness of the material, encompassing both the men and the events they covered, tends to become overwhelming, especially in the absence of incisive comment; the chapters tend to merge into a long string of tributes to the resourcefulness and dedication of the reporters. But their achievements merit recognition: Graham McNamee unveils political conventions in a marathon stint at the 1924 Democratic Party powwow; H.V. Kaltenborn brings a foreign war into American homes from a haystack in Spain; Clem McCarthy tells it in the two-minutes, four-seconds it was at the second Louis-Schmeling fight. Munich rallied listeners around their receivers, and the war kept them there, with reports from Shirer, Sevareid, soldiers and generals on the scene; you can hear it now in the excerpts. After acknowledging the national ascendancy of TV, the authors pay tribute to the vitality of local broadcasting through a visit to one station. The treatment isn't up to the material, but if you foresee interest you may want to tune in.