What are their names?
SELECT T1.Name FROM actor AS T1 JOIN musical AS T2 ON T1.Musical_ID   =   T2.Musical_ID WHERE t2.year  =  1986 and t2.category  =  'Best Book of a Musical' and t2.Result  =  'Nominated'
their names refers to SELECT T1.Name; actors associated with musicals nominated for 'Best Book of a Musical' in 1986 refers to JOIN operation on actor and musical tables with conditions on year, category, and result;