If your request is indeed commercial then we ask you to send us email by following this commercial link. Simply send the email and you will immediately receive back a reply that tells you where you can download an evaluation copy of TTH.
Generally, for licensing purposes, "commercial use" is any use in the course of their employment by someone who works for a company or other entity that provides products or services in return for payment. Examples of commercial use include use by publishers, journals, magazines, businesses, consultants, web-page designers and so on.
If your request is for non-commercial use, then we ask you to send us email by following this non-commercial link. Please mention what your intended use is and what institute, if any, you belong to. You will receive a reply that tells you where to download a non-commercial copy.
The predominant non-commercial use of TTH is by college professors, students, university researchers, and high-schools. We are delighted if TTH can be of assistance in such educational and scholarly contexts; it may be used without charge.
[Please note, if you do not receive an immediate reply to your email, it is probably because your email agent is incorrectly configured. In particular you should ensure that any "Reply to:" line in the message you send contains your full valid email address.]