Letter to Harry Garland from Oliver P. Ferrell, the editor of Popular Electronics, describing the excitement of his technical editor, Les Solomon, for the manuscript “Build the Filoscillator”. This article, by Roger Melen and Harry Garland, was published as a construction project “Build the Fil-Oscillator” in the May 1971 issue of Popular Electronics. In 1973 the project was produced as a commercial product by Dytech Corporation.