What to read after Major Barbara?

Barbara Undershaft is engaged in helping the poor as a Major in the Salvation Army in London. For many years, Barbara and her siblings have been estranged from their father, Andrew Undershaft, who now reappears as a rich and successful munitions maker. Undershaft, the father, gives money to the Salvation Army, which offends Major Barbara, who does not want to be connected to his tainted wealth. However, the father argues that poverty is a worse problem than munitions, and claims that he is doing more to help society by giving his workers jobs and a steady income than Major Barbara is doing to help them by giving them bread and soup.