We moved from the USA to Bangkok in 2002. We shipped a lot of things in a 20 foot container, including about 5 cartons of books, soft back and hard back. They are all still fine. Even the ones stored in rooms where we don't run the A/C regularly.  That said we run A/C enough that the humidity in our house is fairly low. Good luck.

It might depend on where in Thailand you live, I live on a southern island. I had my book collection shipped from Europe in 2007, and for a couple of years all my books stayed in cardboard boxes in a storage room – just a shopunit I rented in the area I live – while I had a house build. 10 years ago the books were unpacked, all in fine condition. I keep them in normal open shelfs and haven't experienced any problems. In the living room we don't use the aircon, in my study I use aircon in warm periods, cooling it down to about 28°. Relative humidity vary between 50 and 80 on my hygrometer in the study; in my home country Denmark we could have 80+ in the summertime.

I amassed quite the collection of books over the 10 years while I was living there. I had them in a cupboard that had slits in the doors and had no rot whatsoever. I guess the key is good ventilation and airing your place out daily. 

Yes, everything will rot.

My wife has a library in our house with thousands of books some of which are very old and she has had no problems with that issue in the 10 years since we built the house. The room has an aircon but it isn't on very often. This is in Bangkok though and it might not be the same in e.g. South Thailand where there can be long periods of relatively high humidity.

 

I have lived in Hong Kong and humidity there definitely is an issue even just with clothes in a wardrobe. Using dehumidifiers and heating elements in closets is common during the humid season. I have never seen those used in Bangkok. 

Ah, yes your intellectual trophy collection. Why bother bringing them here? Won't impress the locals much. ????

Lived in Bangkok for 12 years.  Never had a problem with books rotting due to the heat and humidity.  Almost all were kept in an open bookcase.  Only ran the A/C at night.  

Thailand is death to books. Mine are well-ventilated but accumulate a layer of dust if not cleaned regularly. I keep any book I value in ziplocs.

Dasa Books near Emporium is awesome for secondhand!