Physically the same dimensions as the catalogues & RC Guide books you'll no doubt be familiar with, these include information on how Tamiya works, its history, and photos of the Tamiya factory & offices (inside and out).
The "Tamiya Operations" book was published in 1990, with "Worldwide Operations" appearing in the year 2000; I'm not aware of anything comparable being published in other years.
The content certainly suggests these wasn't a regular thing - "Tamiya Operations", for example features the 1986 Bigwig quite prominently, despite being published in 1990.
From some research these would appear to be very rare publications - but apparently not that desirable or valuable. The "Worldwide Operations" booklet appears to be even rarer than the earlier edition, although it also appears (electronically, obviously) on both the 2001 and 2002 CDROM versions of the Tamiya Catalogue.
Sample Pages from "Tamiya Operations" (1990)
This has 28 pages, 7 of which are in colour.
Sample Pages from "Worldwide Operations" (2000)
36 pages, 11 in colour. It's interesting to compare this with the earlier version - technology has moved on rapidly ... and a lot of production has been outsourced :(
Written by TB member Jonny Retro