Tarsando is essentially correct, but since this topic arises with some frequency, let me add a couple of details.
The great RCA "Living Stereo" LP's of the late 1950's and early 1960's had two distinctive labels, both featuring the RCA dog Nipper with his head cocked toward the mouth of the megaphone of an old acoustic Victrola. The famous "shaded dogs" had a slightly darkened, shaded circle surrounding Nipper and the phono. There were also some excellent recordings released on the RCA "white dogs" as well -- these LP's had the same picture of Nipper, but the picture was surrounded by a white area.
Not all of the "shaded dogs" or "white dogs" were necessarily outstanding recordings, since the quality of the recordings was dependent on the specific recording teams handling the session. The best known recording team was Richard Mohr and Lewis Layton, who consistently produced superb recordings with great fidelity and wonderful acoustic ambience (they did both symphonic and opera recordings). I am fortunate to own some of the original RCA LP's done by the Mohr-Layton team, and I love every one of them, so if you find one of their LP's it is well worth acquiring (assuming the vinyl is in decent shape, and the price is not unreasonable).
Many of the Mohr-Layton recordings have been re-released by various labels, beginning with the LP's from Chesky Records in the latter half of the 1980's. The Chesky LP's were very faithful to the original master tapes, and featured very good (although not the absolute best) vinyl. If you can't find the original "shaded dog" RCA's, then the Chesky LP's are certainly an acceptable substitute.
During the past 10 years, some of the original RCA "shaded dogs" and "white dogs" have also been re-released by Classic Records. These LP's are also of very high quality, with considerably quieter vinyl than the original RCA's.
Last, a number of the "shaded dogs" are also available on CD -- specifically, the JVC XRCD's and the re-mastered versions released on the RCA "Living Stereo" series.
