Multipliers and singular integrals on exponential growth groups

We propose a simple abstract version of Calderón–Zygmund theory, which is applicable to spaces with exponential volume growth, and then show that important specific operators can be treated within this framework. Both authors are part of the European TMR network entitled ``Harmonic Analysis'. The first author was partially supported by KBN grant 5 P03A 050 20 and by the TMR network. The second author was partially supported by his university and by the Italian M.U.R.S.T