Wonder if any TV members have encountered old/antiquarian books in their travels in these countries?

French and British must have imported them. Where are they now? Eaten by termites?

In Vientiane, at the junction of Rue Setthathirat is the cream-coloured shuttered French Colonial National Library. I was in the city on a visa run in 2014 and recall walking past it.

In Vientiane, there are several second hand book shops close to the central fountain. I have previously bought some old dictionaries in one of these shops, Kamu-French and Hmong languages, printed in the early 20th century Very cheap to buy, but somehow I lost the book in a hotel in that city

Yes, many second-hand bookshops in Vientiane, some with old Lao stuff (from the 1960s and before)...but the prices are, for the most part, outrageous, especially when you consider the poor condition they're in. I did buy one myself--the first Lao novel, published in 1942--but only because it was so hard to find and I needed it to create teaching materials for Lao language.

Forget it in Cambodia, for obvious reasons. Don't know about Myanmar.

The Khmer Rouge burned all the books they could get their hands on, very little survived, so rule out Cambodia.

A lot of second hand book stores in Myanmar.

I wouldn't rule out Cambodia. There's not a lot of material for sure but there is some. Bohr's and D's books in Phnom Penh can both be occasional sources of quality stuff. Vientiane has a couple of good second hand bookstores. Thailand has a wealth of them - Chiang Mai in particular but there's very little in the way of antiquarian material in them. Vietnam in some ways may represent your best bet - if it's not anti-communist literature (which is all long gone) - the Vietnamese are a very bookish people but you'll need a hand to find the 2nd hand book shops there as they aren't aimed at English speakers at all. Don't know about Myanmar but will do in about 2 months...