There is not a single book of Meir Kahane that is not a great book. He was not only a great man but also an outstanding writer and thinker.
It is not easy to single out one book as the most suitable one to start a journey into Kahane's works, but I would vote for "Our Challenge". This is a book about Jewish destiny, about the Chosen Land and the Chosen People, about the struggle for the minds and souls of our confused youth, who know so little about themselves and begin to despise themselves as a consequence, about the need for roots and direction in this life.
Alternatively, it is also excellent to start with "Uncomfortable Questions for Comfortable Jews". It deals more with the political situation of Israel than "Our Challenge" but, as always with Kahane, that question is essentially linked with the internal struggle of the Jews, their relation with their identity and heritage, the way they suffer from abnormal feelings of guilt and lack of self-confidence after 2000 years of exile.
"Never Again" is particularly concerned with the moral bankruptcy of the Jewish establishment, the loss of Jewish identity and the need to restore Jewish pride, love of the Jew for the Jew.
"They Must Go" is focused on the recent history of Israel and the challenges it faces, the potential contradiction between the notion of a Jewish state and that of a democracy in the Western sense.
"Listen World Listen Jew" is an impassioned call for the Jewish people to return to their roots through a broad review of history and Zionist themes.
"Israel : Revolution or Referendum ?" deals with the political system of Israel and how to bring about much needed changes.
"Why be Jewish" is focused on the question of what makes young Jews turn away from judaism and issues associated with assimilation in the Galut, such as intermarriage.
"Time To Go Home" deals with the deteriorating situation in the US in the 1970s.