Some particular books I found useful for A Game of Thrones and its sequels deserve mention... Life in a Medieval Castle and Life in a Medieval City, both by Joseph and Frances Gies. --George R.R. Martin, author of the series A Song of Ice and Fire Medieval...
Medieval history comes alive in Frances and Joseph Gies's Life in a Medieval City, used as a research resource by George R. R. Martin in creating the world of A Game of Thrones. Reissued for the first time in decades, Life in a Medieval City is the classic account of the year...