"An author may write their own license or have a lawyer draft one. It is notoriously difficult to anticipate all possible circumstances under which people will want to use and/or distribute the program. For example, may someone put the program on a CD-ROM and sell that? Does it matter whether the CD-ROM contains a collection of software or only that program? May modified versions bear the same name? Even if an author has determined the conditions under which they are making the software available, it is very difficult to properly express these conditions in legally binding terms. A license such as “Permission is hereby granted to use this program in any way and for any purpose, to modify it and to distribute it” does not authorize third parties to distribute modified versions, although this was probably the intent of the author. Unless an author has a compelling reason to do so and is prepared to engage a lawyer to write the license, it is recommended to use a standard license."