Malachi Martin The Jesuits explains what happened to the the most presigious and influential religious order. Did you know that 100 Jesuits petitioned to form a separate order with a traditional Jesuit ethos? There's nothing liberal fascists hate more than the idea that they'll be in direct competition with a non-liberal alternative.
Michael Rose Goodbye Good Men is about seminaries in the USA, with a few references further afield. I've heard the methodology of the book criticised, but it tells the story well enough. The disastrous collapse of moral and academic standards, and the appalling liturgical abuses, of the 70s, 80s and 90s has not been entirely undone, but things are improving. In the meantime, of course, the loss of the good vocations from those years can never be undone.
Ann Carey Sisters in Crisis is about religious sisters (active, not contemplative, and mostly 'sisters', not, technically, nuns). Like Malachi Martin she talks in some detail about the things happening even before the Council which began to undermine the sisters, and were crucial to the rapid spread of liberal innovations during and after it.