In 1971 Scholastic Book Services issued two Three Investigators titles in a large-size (about 8" X 5 1/4") paperback format. Over the course of the next 13 years they would continue to issue various titles from the series in a small-size (about 7" X 4") paperback format. In all they issued 20 different titles. SBS uses a numberline system similar to that of Random House to designate a book's printing history. Some First Printings will actually state "First Printing" and then give the month and year but this isn't the case with all titles.
Thanks to some detective work by fellow collector Kenneth Hopping, we can now determine the year in which each title was printed by Scholastic. In all small-size SBS books printed after 1975, there appear several number sequences near the bottom of the copyright page. For example, here are the numberlines found in a SBS First Printing of #18 Shrinking House:
12 11 10 9 8 7 6 5 4 3 2 1 2 2 3 4 5 6 7/8 01
The first set of numbers indicates the Printing. In this example we have a First Printing since the string ends with a "1". The second set of numbers reveals the month in which the book was printed. In this example, "2" indicates the month of February. Curiously, it seems that this second number-set appears only in First Printings - later printings omit the month. The third set of numbers reveals the year of the printing as encoded by the following formula: 19XY where Yn . . . n/X. In this example X = 8 and Y = 2. Kenneth surmises that the "two additional digits at the end (always 01 or 06) might indicate the academic semester in which the books were marketed." This is a good possibility and it works for many of the books as it does in the above example, but there are a few titles for which it doesn't.
Here then is the order in which the SBS books originally appeared:
TITLE COVER ARTIST FIRST PRINTED TX, TK or ISBN#
#4 Green Ghost (large) Harry Kane Sept. 1971 1916
#1 Terror Castle (large) Ed Vebell Nov. 1971 1917
#11 Talking Skull Harry Kane Sept. 1974 2922
#21 Haunted Mirror Jack Hearne Sept. 1975 3245
#19 Phantom Lake Ed Vebell Jan. 1976 3393
#20 Monster Mountain Jack Hearne Jan. 1978 3943
#25 Dancing Devil Jack Hearne April 1978 3942
#10 Moaning Cave Harry Kane Oct. 1978 4464
#3 Whispering Mummy Harry Kane Jan. 1979 4510
#12 Laughing Shadow Charles Liese Sept. 1979 30053-9
#9 Screaming Clock Charles Liese Nov. 1979 30330-9
#7 Fiery Eye Charles Liese March 1980 30328-7
#15 Flaming Footprints Charles Liese Sept. 1980 30329-5
#8 Silver Spider Charles Liese Feb. 1981 30326-0
#4 Green Ghost (small) Charles Liese Oct. 1981 32320-2
#30 Shark Reef Charles Liese Dec. 1981 31567-6
#18 Shrinking House Charles Liese Feb. 1982 30327-9
#6 Skeleton Island Charles Liese Sept. 1982 30325-2
#32 Blazing Cliffs Charles Liese Jan. 1983 32503-5
#14 Coughing Dragon Robert Adragna Nov. 1983 32833-6
#13 Crooked Cat Robert Adragna Jan. 1984 32504-3
Unfortunately, I cannot account for the apparent discrepancies between the order of the ISBN #'s and the dates encoded in the books. For example, according the the ISBN #s the books would have been issued in a slightly different order than what the encoded dates say but I tend to believe that the printing codes are the most reliable information to use. Quite possibly the ISBN#'s were assigned before the books went to print.
The two large-size books are fairly common as they were both available throughout the 1970's and both contain the original internal illustrations by Harry Kane. Sometime in the mid-1970's these were slightly reduced in height from 8" to 7 1/2" with the widths remaining the same. So technically, there are two varieties of the large-sized books for you completists to look out for. None of the small-size books contain internal illustrations. It is interesting to note that Charles Liese came on board to design new Scholastic cover art for the years 1979 - 1983. It appears, from the "titles available" lists found in the front of the books, that once a Three Investigators title was published by Scholastic, it stayed in their line-up - with one exception: #10 Moaning Cave. This title first appeared in 1978 but was no longer available through SBS after 1981. It is interesting also that Harry Kane provided artwork for this title that is very similar to that found on the original Random House hardbound trade edition - years after he stopped creating covers for Random House.
While many of the SBS books are quite common and, as a whole, do not seem to be highly sought after by collectors, it is no easy task to collect the entire set. Especially difficult are the titles first printed in the 1980's. You can view scans of all of the Scholastic books by going to the Original Series page on this site.