This book summarizes the characteristics and results of a model based on game theory to find optimal scenarios of solution in difficult (hard) negotiations or mediations, where fundamental rights and conventional human rights collide against highly positioned particular interests; with the following objectives: (i) to find the best negotiation strategies to reach win-win agreements under bona fide conditions, out of litis, (ii) to explore flexible negotiation scenarios through scenarios weighted by the parties involved (iii) to analyze the marginal sensitivity of such legal principles to individual conflicting interests, in terms of their opportunity cost, (iv) to objectively estimate the negotiating power associated with the quantitative value of the "Best Alternative to the Negotiated Agreement" (BATA). The above, within the framework of law theory, conflict theory and quantitative methods of economic decision analysis.