During 1990, my S. Korean stamp collection was growing fast, and I had made contact with Michael Rogers INC., from whom I ordered the 1991 KPC-Korean Postage Stamp Catalog.
See the 1991 KPC front cover

In August, 1991, I bought my 2nd SCOTT caialogue; the 1992 SCOTT Standard Postage Stamp Catalogue, Vol. 3.
See the 1992 SCOTT front cover

Sometime, during 1992, I bought Korea's first Official Book, for $135.00. It had 5 specially prepared panes of six stamps in each pane.
See the 1st Official Book

Thereafter, I contacted SCOTT'S editorial staff by phone, they're 35 miles away. My complaint was that they didn't list Korea's Official Books #3, #4, &5; and their listing for Official Books #1 & #2, showed only "pane of 6", and the projected price for only that pane; when in fact both Books contained 5 panes of 6 stamps each. Their reply was that, "they were bound by the policy & procedures as published in the front of each catalogue".
See the 1992 SCOTT page 21A-Booklets

Opinion:
What a rinkey-dink, mickey-mouse policy for a Stamp Cataloguer to take. How arrogant of Scott Publishing Company to think that they could influence or dictate to the Stamp Issuing Authorities of the World, what stamp products they could issue, in order to be listed in Sacrilegious SCOTT Catalogue. Sacrilege, because that's what I charge SCOTT with, for their policy that advocates that dim-witted Stamp Dealers break apart Full-Books of Stamps, in order to equal SCOTT's listing policy of "panes".
And I've seen at least 5 ads, since 1993.

The last S. Korean New-Issued stamp catalogued in the 1995 SCOTT, was the 02-28-1994 "75th Anniversary of the Sam-Il Independence Movement". Immediately before it, SCOTT properly lists the S. Korean Official Book #6, for the 01-24-1994 "The 21st Universal Postal Congress", the first of nine (9) Commemorative Official Books, released by S. Korea during 1994, at Sc# 1765b.
See the poor-scan of 1995 SCOTT page 123
OFF. Book #6

My 1996 Scott Standard Postage Stamp Catalogue, Volume 4, arrived in late July 1995. Ignoring all the extraneous stuff at the front, I promptly flipped to South Korea's latest catalogued stamps. The last catalogued New-Issue, was the Jan. 21, 1995 "Protection of Wild Animals & Plants (2nd Issue)", a two stamp issue at Sc# 1801 & 1802. I was surprised to find the remarks, "Souvenir booklet, 4 #1801" and "Souvenir booklet, 4 #1802"; but, not until I read the footer-remark, "Booklets of Nos. 1801-1802 each have one stamp tied to cover with first day cancel."; did it dawn on me that Scott had begun cataloguing South Korean Collector Booklets. I found one other like remark, after perusal of previous pages of the catalogue; Sc# 1797, 1994's "Philately Week Special".
See Scott# 1801 & 1802, on page 128.
See Scott# 1797, on page 127.
See the 1996 SCOTT page 20A-Booklets;
    Did they change their Booklet policy?...NO!

The 1996 SCOTT, also properly listed S. Korea Official Books #11-14, for the 08-22-1994 4-stamp issue "The 21st Universal Postal Congress", and Official Book #15, for the "Narcissus" definitive stamp, the Book being released 02-28-1995; but, DID NOT list Official Book #7 at the 06-13-1994 1-stamp issue "PHILAKOREA 1994 World Stamp Exhibition", or Official Books #8-10, for the 08-16-1994, 3-stamp issue "PHILAKOREA 1994 World Stamp Exhibition".
OFF. Book #7
OFF. Book #8-10
OFF. Book #11-14
OFF. Book #15

When my 1997 Scott Standard Postage Stamp Catalogue, Volume 4 arrived, the last catalogued New-Issue, was the Mar. 5, 1996 "Protection of Wild Animals & Plants (3rd Issue)", a two stamp issue at Sc# 1865 & 1866.
See Scott's page 122.

The 1997 SCOTT, also properly listed S. Korea Official Book #16, for the 03-20-1995 Definitive stamp issue, "Celadon Pitcher", and the Official Book #18, for the 08-14-1995 Commemorative stamp issue, "Liberation Day, 50th Anniv."; but, DID NOT list Official Book #17, for the 06-01-1995 Definitive stamp issue, 390 Won, "747 flying up to the left".
OFF. Book #16
OFF. Book #17
OFF. Book #18
See the 1997 SCOTT page 22A-Booklets;
    Did they change their Booklet policy?...NO!

When my 1998 Scott Standard Postage Stamp Catalogue, Volume 4 arrived, the last catalogued New-Issue, was the Dec. 2, 1996 "1997 New Year's", a two stamp issue at Sc# 1893 & 1894; erroneously catalogued with the issue-date of "1997, Dec. 2".
See Scott's page 154.

A search showed that there were thirteen (13) new "Complete Booklet" remarks, after those identified for the 1997 Scott, and 121 new "Complete Booklet" remarks, other than those identified for 1996 & 1997, with the earliest shown at Sc# 1535 the May 27, 1989 issue. Plus, a new "Souvenir Booklet Box", has been added at the bottom of Page 145. The "Souvenir Booklet Box" does not contain any Sc# of the Type 2-Portable Booklets remarked.
See "Souvenir Booklet Box" on page 145.

Read what the 1997 STANLEY GIBBONS, Part 18, page 278 has to say about "Philatelic Centre Booklets":
What the 1997 SG's has to say about "Collector Booklets.

The SCOTT listing for Official Books #8-10, finally showed in the 1998 SCOTT, along with Official Book #19 containg the 400 won Definitive stamp of a 747 flying to the right, issued 03-27-1996; but the listing for Official Book #7, and Official Book #17 haven't showed through 2006 SCOTT.
OFF. Book #19
OFF. Book #20-21
See the 1998 SCOTT page 26A-Booklets;
    Did they change their Booklet policy?...NO!