A Complete Three Investigators
U.S. Editions "Master Set"
What is a complete U.S. editions Three Investigators "Master Set"? 

A U.S. editions Master Set is a collection containing at least one copy of each title in every known U.S. edition/format of the Original Series, the Book of Mystery Puzzles, the Find-Your-Fate books and the Crimebusters series.
Additionally, a Master Set will include books in the same edition which display alternative cover art.  For example, a collection containing one example of each of the 43 titles in the GLB edition is not complete.  A Master Set will 
contain at least two copies of titles #4, 5, 13, 17, 20, 21, 22 and 23, one copy having the original cover art and one having the later Adragna cover art.

What isn't required of a Master Set?

It isn't necessary for a Master Set to include examples of every printing of every title.  For example, one hardbound trade edition copy of, say, "Coughing Dragon" would fulfill the requirement.  One doesn't need to acquire a First Printing with 14 titles on the back cover and no ISBN, a second printing with 14 titles on the back cover including the ISBN, a third printing which lists 16 tiles on the back cover and later printings with 18, 20 and 22 titles on the back cover, etc.

First Printings.  While most advanced collectors strive to acquire the earliest or First Printing of each title in each edition, this is not a requirement of a Master Set.  However, see the Unresolved Questions section below for possible exceptions.

The condition of a book.  As long as a book is complete and intact, condition doesn't matter.

Unresolved Questions:  

1.  Should a Master Set contain copies of "Stuttering Parrot" which display both the wap-around cover art and the yellow spine cover in both the hardbound trade and GLB editions?  I believe it should.

2.  Should a Master Set contain First Printings of "Terror Castle" and "Stuttering Parrot" which both contain some printing errors AND a later printing of both titles in which the printing errors were corrected (and in which the bindings are glued as opposed to the stitched bindings found in the true First Printings)?  Again, I believe so.

3.  In general, I don't think it's necessary for a Master Set to include copies of books which have different prices printed on the covers.  However, on the 1998 paperback Dodge edition of "Terror Castle", there are copies which have a bright yellow sunburst printed near the center of of the cover art which promote the sale of this book for 99 cents.  Should a Master Set contain copies with and without the sunburst, or simply one of either?  My opinion is that a Master Set should contain both in this particular case.

4.  Should a Master Set contain the six T3I titles that were part of the Random House Reading Program?  I should think that any advanced collector would strive to include copies of these in their collections but I don't consider them a requirement for a Master Set.  The same is true for Advance Reading Copies, signed books, original artwork and other ephemera.

A breakdown of the contents of a U.S. Editions Master Set (279 books total):

Original Series (244 books):

- Random House Hardbound Trade Edition #1 - 28.  Must include First Printings of both #1 and #2 along with a later
   printing of each of these two titles.  Should also include glossy cover examples of #4, 5, 11, 13, 16, 17, 19 and 20.
   38 books.

- Random House GLB Edition #1 - 43.  Must include First Printings of both #1 and #2 along with a later printing of
   each of these two titles AND later printings of #4, 5, 13, 17, 20, 21, 22 and 23 with the Adragna cover art. 53 books.

- Windward Paperbacks of #1 and #2 with both the white covers and silver covers.  4 books.

- Marchesi Paperbacks #1, 2, 3, 6, 7, 8, 9, 10, 11, 12, 15 and 18.  12 books.

- Marchesi Boxed Sets #1 and #2.  8 books.

- Hitchcock Paperbacks #1 - 6 and 9 - 30.  28 books.

- Keyhole Paperbacks #1 - 43.  43 books.

- Scholastic Paperbacks #1, 3, 4 (2 copies, Kane and Liese covers), 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 18, 19, 20, 21,
   25, 30 and 32.  21 books.

- Weekly Reader Hardbound #3 and #12.  2 books.

- Knopf Bullseye Paperbacks #1, 2, 9, 10, 11, 21, 26, 32, 33, 35, 36 and 39.  12 books.

- Dodge Paperback #1 - 11.  Including a copy of #1 with the yellow sunburst promo.  12 books.

- Dodge Hardbound #1 - 11.  11 books. 

The Book of Mystery Puzzles  (1 book)

Find-Your-Fate Series  (8 books):

- Random House Paperback; all 4 titles

- Random House RLB (hardbound library binding); all 4 titles

Crimebusters Series (26 books):

- Knopf Paperbacks #1 - #11.  11 books.

- Large-sized Knopf Bullseye Paperbacks #1 and 2.  2 books.

- Weekly Reader Hardbound books #1 and 6.  2 books.

- GLB Hardbound #1 - 11.  11 books.

"Sitting on their shelves like well-fed elves."  Just for fun, here's a partial peek into my Library of Mystery and my attempt (as of January 2012) at building a Master Set of U.S. editions.  It contains more than is required as outlined above but I like collecting some re-bound library books and related ephemera.
This page is an unfinished
work in progress.  Feel free to e-mail with your thoughts, opinions and suggestions.