This book identifies the constant and the variable aspects in Hamas' ideology, between the ones articulated in its Charter of 1988, and the ones articulated in its Document of General Principles and Policies issued in 2017. It addresses three main areas: Hamas' view of the borders of the Palestinian state, Hamas' exercise of power in relation to its concept of resistance (shifts in its interpretation of the resistance action), and Hamas' orientation towards the peace process. The book discusses the changes in Hamas' stance towards the borders of the Palestinian statehood (Two States Solution), the Armed Resistance, and the Peace Process. It explains Hamas' perceptions on these issues after assuming power and becoming a government. Additionally, it analyzes the variables that affected Hamas' political calculations and motivations behind its participation in the Political Process and the issuance of the New Political Document in May 2017 that articulated its stance toward the Two States Solution, the Armed Resistance, and the Peace Process.