Fair use and copyrighted materials explicitly stating not to use I am currently sourcing some ideas from a few books (through Google Books) and I sometimes stumble upon introductory messages from the authors/editors of these books saying something like:

"All rights reserved. No part of this book may be reprinted or reproduced or utilised in any form or by an electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers" (https://books.google.com/books?isbn=1317622006)

and similar messages... so, does that mean that I cannot paraphrase or quote from it under fair use? (Sometimes I do read other messages explicitly allowing fair use)
This is fairly standard boilerplate in UK-published books. You'll probably find that all books from this publisher have identical text, with gentle shifts in phrasing over the years as they refine it.

This statement is effectively saying "to be clear, we don't give you permission to do any of the things that the law requires you to have permission to do, and you can't pretend you didn't know this". However, it will not prevent you doing anything you would otherwise have been allowed to do as reasonable fair use/fair dealing/etc by local copyright law - generally speaking, the publisher cannot prevent such use.

Incidentally, "other means, now known or hereafter invented..." is a relatively new addition - it's a reaction to ebooks! I have a collection of essays where the editors were feeling playful and added "or magical" in here...