If the difference between PIJ and Hamas disappeared once the latter took up arms, why did PIJ survive as a separate organization with a justification for existence? I proceed through four sections in this chapter. First, I present the historical argument, which elaborates on the historical causes for the emergence of PIJ and why it did not merge with Hamas subsequently once the latter was founded. I then proceed to present the ideological argument in the second section. The third assesses the socio-geographical argument, in which I discuss whether PIJ has a distinct class character and geographical distribution that sets the movement apart from Hamas. I conclude this chapter by outlining the implications and limitations of this study, in addition to suggestions for future research on PIJ.