The year is 1994, the scene is me and one of my junior high friends talking about philosophy. He has shown me a volume he has just acquired: The Viking Portable Nietzsche, which I remember had a distinctive purple cover. We were an intellectual lot in junior high, although apparently only intellectual enough to know about Nietszche, the dimestore existentialist who is usually first encountered by adolescents wishing to have philosophical justification for hating the system. But I digress. He proudly stated that now that he had the Viking Portable edition, he could now study Nietszche in an easy, portable format, and no longer had to carry around his library of Nietszche's works in a wheelbarrow.
Although that is an adolescent exaggeration, that was the basic premise behind the Viking Portable Library, a series of books that were published widely between the 1940s and the 1970s, and which, due to their large volume and widespread distribution, were easily found in used book stores and thrift stores from then until the present day. Each book would take a famous author, such as Mark Twain, Dante or Jonathan Swift, and publish their most important works, as well as excerpts of other works, together with correspondence or diaries, to give an all around picture of their life and writings. They also usually had extensive introductions, written by experts. They were large books, usually averaging well over 600 pages. They were all based around authors whose work was in the public domain, so that they had very low production costs there. They were usually quite well produced, however, with the editors of the volumes being well known writers in the field. Along with books focusing on a single author, some volumes were anthologies of a single nation's work, or of a time period, such as with the "Irish Reader" and "The Medieval Reader".
They were great books, and if I find a volume on sale, I always pick it up, even if I may not get around to reading it. The only complaint against them is that often the assortment of writings they have might not give a full scope on that particular author--- although, of course, they never claim to do so, being as stated just a "portable" version of that author's works.
After the initial Viking Portable Library was printed, they reprinted many of them as Trade Paperbacks, and apparently Penguin Books now is the publisher of the line. While I am sure they are doing a good job at it, such works probably don't have the sentimental value that the original Viking Paperbacks have for me.