I know Texas is rather strict on hunting private land without the permission of the owner. What information/proof should one expect/want to see from a hunting guide that he has the proper permission to guide you on that parcel of land?

Honestly I think you do the research first and pick a guide with a great reputation.

Thats the first step, if in doubt ask a guide exactly where you will be hunting then call a game warden and ask him/her.

Good answers all. You can also watch for evidence of anything shady during the hunt and call it off if you get uncomfortable.

As for me, I don't have any actual letter or anything giving me permission. My landowner agreements are verbal. However, I do have liability release forms from the ranch as well as the combinations to all the gates. If we run into the landowner or workers on the ranch you will also see that I have permission to be there.

I would definately agree with Michael on this. Combos to the gates are a great start and together with liability forms would make me pretty comfortable.