Paula Byrne’s Mad World: Evelyn Waugh and the Secrets of Brideshead scores several significant breakthroughs, and I warmly commend it to general readers as well as Waugh enthusiasts. It follows hard on the heels of Jane Mulvagh’s equally interesting Madresfield: One Home, One Family, One Thousand Years. The books are complementary. Mad World is a biography of Waugh that works outward from his close friendship with the Lygons of Madresfield. Mulvagh’s Madresfield begins and ends with (unremarkable) chapters about Waugh but is essentially a fascinating history of Madresfield, a country house with a Tudor core and enveloping Neo-Gothic extensions, and…