New York: Bell Telephone Laboratories December 1950. Later printing. 9 pages, 4to. 8 3/8 x 10 7/8 inches. Original printed wrappers; perforations for ring binder as issued. Some light browning to the covers near the spine. Clean internallly, bumped lower corner of spine. Near Fine. Stapled wraps. 
"Some new experiments in transistor electronics are described here in which concepts suggested by theory have been verified directly by experiment." (abstract)
First presented at the 19th Joseph Henry Lecture before the Philosophical Society of Washington, Washington, DC, May 13, 1950, this edition printed December 1950. Originally published in Physics Today Vol. 3, pp. 16-24, October 1950.
Most often distributed via subscriptions to libraries, copies of the Bell System Monograph series without library markings (as here) are not common. Although we have not seen one, we have to assume there was a Physics Today (October 1950) offprint of this article which would predate this December, 1950 printing by a few months. Hence we've identified this as a later printing rather than the first separate printing.
"William Bradford Shockley Jr. (February 13, 1910 – August 12, 1989) was an American physicist and inventor. Shockley was the manager of a research group at Bell Labs that included John Bardeen and Walter Brattain. The three scientists were jointly awarded the 1956 Nobel Prize in Physics for "their researches on semiconductors and their discovery of the transistor effect". Partly as a result of Shockley's attempts to commercialize a new transistor design in the 1950s and 1960s, California's "Silicon Valley" became a hotbed of electronics innovation." (wiki)