The city of Thessalonica has at times been called Salonika. We shall use this name for it because it is easier.
Most people think that Paul and his friends wrote this second letter to the church at Salonika soon after they wrote the first letter. [0.1] Paul, Silas and Timothy are still together. They probably sent the letter from Corinth, like the first letter. Chapter 1:4 speaks of 'God's churches'. This may just mean that Paul and his friends had started churches not only in Corinth but also in other places around there (Rom.15: 19; 16:1). But this need not be the meaning. News about the church at Salonika still reached Paul. Some of the problems in the church at Salonika were worse. The writers say nothing about some of the problems in the second letter, so we think that they had been settled.
We think that this letter, like the first one, is largely the work of Paul. So we shall speak of Paul as the writer, but we remember that Silas and Timothy were with him.