True caller is the best way to know the name and city of the person who is calling you. The best feature is it also give information about any number if that is spam or not. Moreover, recently it has also started the True SMS which gives information about from which person the sms has been came too.
It gives you easiest way to pick up call which are important to you and do not pick those which are not. Moreover, it also has web version where you can use your username and password and verify any mobile number this is good initiative to catch those who play around like road romeo or harrashing us.