As luck would have it, poking through old facebook posts I eventually found not one but two different versions of the text I was looking for – and a great deal of other interesting material with them.
The Spy With My Face 1965 UK Pressbook
1964 Promotional Booklet
1966 Film Review article on One Spy Too Many
The better-quality version comes from a set of scans from the UK promotional booklet for the second UNCLE film, The Spy With My Face, which opened in London in August 1965 (credit for those goes to Evelyn Turner over on the The Man from U.N.C.L.E. - Inner Circle group – I just stitched 'em together and checked if she'd mind seeing them posted elsewhere).
I also chanced upon much lower-quality scans of another version of an original 1964 promotional booklet – this one in black and white, but featuring a complete version of the text I was looking for. Quality in those scans are so poor that they take some deciphering, so I've transcribed the complete text for the pages I was most interested in. Full text is under the cut below. (The text of the character bios from the same booklet can be found in my original post about character bios.)
The last set of scans comes from a March 1966 Film Review article on the season 2 film One Spy Too Many. The text there doesn't reproduce the descriptions of UNCLE and THRUSH in full, but was obviously written by someone who was referencing them, showing that the original text was still being used and reused in promotional material well into the second year of the show. Also notable (at least to me) is that it refers to Napoleon to as "Chief Enforcement Agent" – a popular title around fandom and fanfic, but one that had puzzled me, since it never does appear anywhere in either the episode dialogue, or in Napoleon's original pre-series bio. Clearly, however, fans weren't getting it from nowhere.
Introducing U.N.C.L.E. and a new experience in TV entertainment
In New York City's East Fifties, a few blocks from the United Nations enclave, there is a row of buildings consisting of a large public parking garage, four dilapidated brownstones and a modern three-story whitestone.
The first two floors of the whitestone are occupied by an exclusive "key club" restaurant named The Mask Club. It features fine food served by waitresses wearing masks (and little else) to patrons who also don masks as they enter... masks that are grotesque caricatures of their dominant features. (The purpose is to be different, exclusive, expensive and frivolous.). The third floor has been converted into a suite of sedate offices entered through a door on which are engraved the letters U.N.C.L.E.
If you could peel away the outer skin of the decaying brownstones, you would find to your surprise that they completely hide a modern three-story office building staffed with alert young men and women of many races, creeds, colors and national origins... as well as a bewildering array of modern machinery for business and communication.
Further investigation would disclose, below the basement level, an underground channel leading to the east River, where several fast motor launches are anchored out of view of prying eyes.
A climb up to the roof and an examination of the large neon-lighted advertising billboard might lead to the additional discovery that its supporting pillars conceal a high-powered shortwave antenna and elaborate receiving and sending gear.
This unsuspected complex is the heart, brain and body of U.N.C.L.E., the organization that occupies the sedate third floor offices of the whitestone, owns all the adjacent buildings, employs everyone who has access to them and has a passion for anonymity.
U.N.C.L.E.'s business is to protect the welfare and interests of people and nations anywhere in the world from the forces of organized evil operating on an international scale.
If this all sounds slightly improbable, why don't you stroll over to First Avenue, amble through the fashionable East Fifties yourself, and try to locate the brownstones that camouflage U.N.C.L.E.'s headquarters?
The main offices – and the organization
In the three-story building concealed behind the decaying brownstones to which there are four known entrances, is a maze of steel corridors and suites. There are no staircases in the building, four elevators handle the vertical traffic.
If such a thing as an Organization Chart of U.N.C.L.E. were to exist, it might break down the personnel into six sections... each subdivided into two departments, one of which overlaps the functions of the department just below it.
At the very pinnacle of the power structure are five men of different nationalities who head up the Policy and Operations Department. Nobody knows how these leaders enter or leave their offices. (Could there possibly be a fifth entrance to the building above which no one, except these five men, is aware?)
The five other departments, in descending order of rank, are: Operations and Enforcement, Enforcement and Intelligence, Intelligence and Communications, Communications and Security, and Security and Personnel.
U.N.C.L.E.'s personnel are multi-national and multi-lingual. When they face a problem of communication, or in times of stress or where secrecy is especially desirable, they will lapse into the language of interlingua. This is a simple international language used mainly by people in scientific circles. Otherwise, these men and women probably will manage to make themselves understood in a fairly respectable form of English.
Improbable as an organization such as U.N.C.L.E. may appear, it does exist. So, too, does a nation called Thrush.
If you were to examine the globe carefully, you would not find Thrush's name engraved anywhere on it. Yet time and time again, as you passed your hand over country after country, you would have placed your fingers (unknowingly) on territory under the domination of Thrush.
For Thrush is a supra-nation, without geographical boundaries: a series of self-contained units in various sections of many countries of the world. Those units, or satrapies, may take the form of a manufacturing complex, or a school, or a chain of underground tunnels and caverns, or a department store. They exist as a functional part of the society in which they are located. But they have a shadowy existence all their own, a secret life in which their personnel dedicate their fanatic loyalty to Thrush.
Thrush's inflexible purpose is to dominate the earth.
There is an almost governmental structure of authority in THRUSH. At the top is the Council: a group of men and women, all leaders in their various fields, almost all super-intellects. These scientists, industrialists and intellectuals hold positions of importance in their various countries through routine channels and social living. But no matter where they reside, they pledge their allegiance to Thrush, as do their minions, the lesser men and women who execute Thrush's commands.
At regular intervals, the Council members meet at Thrush, the capital city from which the organization takes its name. This capital also is concealed under a specific "cover." But, unlike the other satrapies, it is mobile, constantly shifted from place to place, from country to country, from land to underground to sea to air and back. It never is allowed to stay in any one place long enough for any enemy to locate and destroy it.
Thrush's capital contains every necessary function to sustain human life under any condition and all the adjuncts of a government. It was its army, its clerks, its various divisions and compartments, its echelons of leadership. Variations on these elements also appear in the satrapy units of Thrush.
The Ultimate Computer
Most important of all, THRUSH has the Ultimate Computer. All decisions of the council are made by this apparatus. An almost infallible thinking machine, it has been developed by the brightest minds of Thrush. The Council collects all information on any subject or endeavor, feeds the information to The Ultimate Computer, then follows the plan of action developed by it. When Thrush fails, it is not due to any flaw in The Ultimate Computer but human failure or to superior enemy personnel.
With its overwhelming resources and vast reservoir of brains, money and power, Thrush is a potent force which does not hesitate to use any form of evil to attain its ends.
While its enormous treasury is replenished constantly through illegitimate as well as legitimate enterprises, THRUSH is far more than a mere international clique of clever criminals. It is a tightly organized world-wide syndicate that has at its command all the newest weapons, methods of communication and transportation facilities, plus research and industrial components that would do credit to any modern country.
Led by a group of super-intellectuals under the guidance of The Ultimate Computer and dedicated to a policy of self-aggrandizement at the expense of all others, this supra-nation is at war with everyone. Thrush has no allies. Only enemies. If you are not on Thrush's side, you are marked to be ruled or destroyed.
Thrush's principal antagonist is U.N.C.L.E.
It's interesting to compare these early concepts to what actually appeared on screen. Many prominent details never made it into the show, like the Mask Club, the tunnel to the river, and virtually everything said about THRUSH. In other places, the show incorporates some details only to outright contradict others. THRUSH's Ultimate Computer, for example, becomes a plot point in The Ultimate Computer Affair, but is there presented as a relatively new development which UNCLE must destroy before it reaches completion. In The Discotheque Affair, we discover that UNCLE rents out a number of apartments in the block that makes up HQ to civilians who have no notion about the true nature of their landlords, which certainly contradicts the idea that UNCLE "owns all the adjacent buildings [and] employs everyone who has access to them". Additionally, given that Napoleon mentions taking the stairs in The Mad, Mad Tea Party Affair, we can presume the UNCLE building of the show wasn't the elevators-only emergency-access deathtrap described here, which may be some small relief. ;)
The notion of there being "four known entrances" to UNCLE is also debatable, since, counting Del Floria's, the parking garage entrance from Deadly Decoy, the helipad seen in Summit-5, and the underground channel explicitly described in the text here, we've already got four entrances – even before we add in the usual supposition that there's an additional entrance through the Mask Club, and another through a charitable organisation which forms the propaganda front for UNCLE in the same complex. (How many entrances was that again?) The "fact" that UNCLE has exactly four known entrances (not counting Mr. Waverly's "secret" entrance) is nonetheless an oft-repeated piece of UNCLE lore. Speaking of which, there's no mention here that the Mask Club acts as an after-hours entrance to UNCLE, or of any charitable foundation at all – though these could well have been details from some other prospectus or version of the writer's notes which fans have got hold of over the years.
Also of some minor interest is how things vary between the different versions. The 1964 text lists only the original six UNCLE Sections from Rolfe's earliest notes, from Policy and Operations to Security and Personnel. The 1965 version adds in two extra Sections that appeared in a variety of later material, "Propaganda and Finance" and "Camouflage and Deception". However, the original version was clearly still getting some circulation as late as 1966, because we're back down to just those first six again in the Film Review article.
There are a few other minor changes in the UK promotion booklet, such as using British spelling and switching references to the "brownstones" and "whitestone" to apartment buildings and a house, presumably because British audiences wouldn't be familiar with the original terms. Neither the promotional material for The Spy With My Face or One Spy Too Many include Waverly's bio, though both describe Waverly as being in the habit of surprising Napoleon by showing up in the field and "tsk-tsking" him as he hangs from some deathtrap – an image that comes directly from the text of his pre-production bio, but which never did appear in the show. It's a great image though, and it certainly feels very Waverly, so I can hardly blame the editors for latching onto an excuse to share it.
The UK booklet also includes brief biographies of some of the star actors, adds some chatter about tongue-in-cheek heroics, drops some trivia about the fanmail received by the UNCLE gun, and finds two different places on the same page to let us know how handsome David McCallum is (more amusingly, it also tries to tell us he's still in his mid-twenties). If you're at all interested in how UNCLE was promoted in its own time, it's a fun little read.