"One of the main problems for the record producer is finding suitable material.
This is especially true when you are recording someone like Matt Monro or Shirley Bassey, who don't write their own songs. It is the job of the producer and people in the business know that you record Matt, or Shirley, or Cilla Black, they will send you songs with those people in mind. Even the public sends offerings. But that is not enough. You still have to search. You still have to ring up the publishers' offices.
You might think that they should be smart enough to send the stuff without being asked. But everyone isn't smart all the time. Sometimes, if you push them enough, they may produce something which they have not thought of as suitable anyway, because they tend to send you only the obvious ones. If you have had a hit with Cilla Black called 'You're My World', the next three months' mail will consist of songs exactly like 'You're My World'. It will not occur to anyone that you and Cilla might be interested in 'You've Lost That Loving Feeling' or 'Baby, It's Cold Outside'.
Ideally, the producer should try not to stick to the same thing." (George Martin, 1979)