The following pages contain the solutions for all the problems to be found in Chapters 14, 15, and 16 of Part II of the textbook A First Course in String Theory. The handwritten solutions are due to Jeffrey Goldstone. The rest of the solutions have been typeset. They were mostly written by me. In chapters 14 and 15 the solutions of problems related to string models were based on those of Daniel Gulotta and Clayton Featherstone.