New York, NY: Bell Telephone Laboratories, Incorporated March 1951. First Separate Edition. 48 pages. Self wrappers. Blue cloth spine over stapled printed grey, black and blue wrappers. 5 hole punched at spine as issued. A bright clean copy noting soft bump to upper corner and some minor discoloration to rear cover. Near Fine. Wraps. 
Bell Telephone System, Technical Publications, Monograph 1813. First published in the Bell System Technical Journal, Vol 29, pp 560-607, October 1950. Here as the first separate edition. Early theoretical work on semiconductors.
COLLECTORS NOTE: The Bell System Monograph series is not an offprint series although it is often incorrectly referred to in this manner. It was rather a publication of Bell Telephone Laboratories used to widely distribute (primarily to libraries and large corporations) research articles written by Bell System employees in a variety of widely dispersed publications (including but certainly not limited to the Bell System Technical Journal). The series therefore represents a much broader selection of Bell System research than the Bell System Technical Journal did. Collectors prize this series as they are often (but not always) the first separate appearance of a paper and hence are the closest one can get to the elusive and ever sought after offprint.