I am am going to be traveling to Bangkok, Siem Reap, and Vientiane in a few weeks. I am hoping to read a non-travel book that gives a broad outline of the history of Southeast Asia from Ancient to modern times. Do you guys know of any that would place greater emphasis upon the area that I will be traveling than Vietnam for example. Thanks for your help.
Anthony Reid, A History of Southeast Asia: Critical Crossroads (Blackwell, 2015).
Keep in mind none of the general histories will focus on Thailand, Cambodia, and Laos to the exclusion of the other SE Asian states, so you'll have to jump around a bit. But this is one volume that goes from pre-modern to modern, rather than having it broken into different volumes.
Adding to /u/Lich-Su, Nicholas Tarling wrote a good overview though I can't remember where he stopped. Can't beat Miksic's Silk Road of the Sea for 1300-1800 and now there's a new volume due out. * excited *
... while writing this, I also just noticed that NUS press has randomly discounted a bunch of its history books to as little as $5 so I'm going to go give myself an early christmas present.