The diaries of the fourth duke of Newcastle-under-Lyne (1785-1851) provide an unrivalled insight into the politics of the 'age of reform', during the late-1820s and 1830s, from the perspective of a prominent political critic. Newcastle was a well known defender of the constitutional status quo and used his position in the house of lords, his family's historic electoral influence and personal contacts with the leading royal and political figures of the day to argue the case against change. He was also a leading participant in ultra-tory parliamentary groups such as the 'king's friends' and the...