New York: American Telephone and Telegraph Company 1949. First Edition. viii, 753 pages. 8vo. Dark blue/black cloth with replaced endpapers. Page edges speckled. Spine lettering "Bell System Technical Journal" | "Vol 28, 1949". Ex-libris "P. Caporale" with owner's name lettered on front panel and signature on front pastedown endpaper. This volume includes all 4 quarterly issues of the Bell System Technical Journal for 1949. Original wrappers are not bound in as is often the case. A sound copy. Near Fine. Cloth. 
Bardeen, Brattain and Shockley won the Nobel Prize in Physics in 1956 "for their researches on semiconductors and their discovery of the transistor effect." The first paper referenced here, 'Physical Principles Involved in Transistor Action' is the classic paper on the subject, here in it's original publication format. The same paper was published simultaneously in the April 15, 1949 issue of the Physical Review.
This volume also contains a paper by Claude Shannon 'Communication Theory of Secrecy Systems' which was originally published in a classified memorandum 'A Mathematical Theory of Cryptography' in Sept 1, 1945. It was declassified, and published here for the first time publically.
There are also other papers on the transistor, and papers by other Bell System researchers. The Bell System Research Labs functioned as a rich incubator during this period, turning out key developments across many technologies. The Bell System Technical Journal is an important journal of record for research in electronics, physics, communications theory, and mathematics.
Shannon, Collected Papers #24 (original memorandum publication) and #25 (this publication, which is noted as superceding the original memorandum). Origins of Cyberspace 450.