This is THE reference for koine greek (the language of the New Testament). This particular version is not the latest, lacking the revisions of Danker, but for the interested amateur like myself, especially one on a limited budget, it is just perfect. One note: It is not an analytic lexicon, that is, it does not list every form of words explicitly so you do need to be able to parse words to get the base form to use it, but there are relatively cheap analytic lexicons that make good companions to this for those still learning the language. Also, for those wanting to work on other early Christian documents this lexicon includes words found in such works whereas most NT lexicons only include words found in the New Testament itself.