You are now purchasing one copy of Language, Proof and Logic, 2nd edition package for $55.

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  • Please check that you are purchasing the correct package.
    • Our packages are not interchangeable. In particular, registration keys for one package will not allow you to use the Grade Grinder to assess exercises from the other package.
  • The purchased products will be registered to the given name and email address. Registration is non-transferable.
  • You are responsible for ensuring that your computing platform meets the requirement for running the software. We support most current versions of the Windows and Macintosh operating systems. The Language, Proof and Logic and Tarski's World packages are also available on Fedora and Ubuntu Linux platforms, but are not supported. We have no plans to support Logical Reasoning with Diagrams and Sentences on any Linux platform. See the FAQ for more details.

Paperless Package