The book investigates the variants of intercooler effectiveness on exergo-economic and exergo-sustainability indicators of modified Brayton cycles. The objective is to ascertain how the variant in the intercooler effectiveness affects the exergy-based parameters. However, to achieve this, a component by component exergy-cost balances was established. The considered cycles include: the non-specific cycle (Case 1) comprising a gas turbine (GT), intercooler (IC), heat exchanger (HE) and reheat system (REH), others include (GT+H +REH +ST, Case 2), (GT+HE +IC +REH +ST+FWH, Case 3) and (GT+HE+IC+REH +ST+2 FWH, Case 4). The calculated cycle efficiencies (Cases 1 to 4) varies from 17.59 to 28.84 % for intercooler effectiveness of 0.75 and 0.95. The exergy destruction within this range was 0.97 %, 1.26 %, 0.89 % and 1.23 % (Cases 1, 2 3 and 4) respectively. Conclusively, the intercooler and other modifications have a marginal effect but Cases 4 and 3 was most sustainable with considerableESI.