That's the one I referred to which was issued on the 50th Anniversary of ICH. Called "A ROOM WITH A VIEW OF THE WORLD", it was published by Weidenfeld and Nicolson of London in 1996, but alas is out of print and even ICH cannot get copies. However, as noted by tristan727, one can generally find a copy at any IC property, either in the Club IC Lounge or by asking the manager if you can borrow a copy. Most recently I leafed through the Spanish language version in the Club IC lounge in Buenos Aires.

I believe Hilton International was owned by UA for a very short period and then quickly sold off, though you are right about Hertz and the aforementioned Westin being part of the short-lived ALLEGIS. It has been British for several decades now, owned by the Ladbrook gaming folks. Though it was started as a spin off from the American Hiltons, which dumped its non-US properties back in the 1960s or early 70s. As a part of that agreement, Hilton USA could not open overseas properties under the Hilton name. This led to the establishment of the high end Conrad brand for a limited number of major city properties outside the USA. I believe Hilton International forged a link with TWA through the 70s, when that carrier began to lose its international cachet.

Remember, in the 50s airlines were just getting established and served a fairly wealthy clientel who demanded top quality hotels which didn't really exist in most cities. Their customers were wealthy, business or showbusiness, or diplomatic types. Trippe's idea was one would drive business to the other, but like the chicken and egg, needed one another to generate more business. Worldwide, IC developed a brand that became synonomous with class, and it developed quite a niche with the diplomatic community, including their darker side, as alluded to, the CIA and its parallels in other countries. It is no coincidence IC has many properties throughout the third world and is the hotel chain of choice among foreign correspondents too, when they emerge to "safe zones" from their assignments behind the lines. And no coincidence that IC's benefits program is called AMBASSADOR!