"Begg, Dornbusch and Fisher" for a one-volume treatise on Economics. That was my Economics 101 book last century, but constantly updated and revised the recent

"Begg, Dornbusch and Fisher" for a one-volume treatise on Economics. That was my Economics 101 book last century, but constantly updated and revised the recent editions are still topical and clearly explained Dornbusch and Fisher also publish a standard one-volume treatise on MacroEconomics which might be a better fit for your country-level requirements.