This book-- The TOMProgramming Language--, the language it describes, and the tools discussed, (collectively denoted `software' in the following) are free; this means that everyone is free to use them and free to redistribute them on a free basis.
Specifically, we want to make sure that you have the right to give away copies of the software that relate to TOM, that you receive source code or else can get it if you want it, that you can change the software or use pieces of them in new free programs, and that you know you can do these things.
To make sure that everyone has such rights, we have to forbid you to deprive anyone else of these rights. For example, if you distribute copies of the TOM related software, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must tell them their rights.
Also, for our own protection, we must make certain that everyone finds out that there is no warranty for the software that relates to TOM. If the software is modified by someone else and passed on, we want their recipients to know that what they have is not what we distributed, so that any problems introduced by others will not reflect on our reputation.
The precise conditions of the licenses for the software currently being distributed that relates to TOM are found in the General Public Licenses that accompany them.