There are some ebooks that are readily available as PDF, and can be downloaded from multiple sources. For example, "Effective Java" by Joshua Bloch can be found easily on the web. There are even repositories on Github containing multiple ebooks on programming.
In "Effective Java" the following paragraph can be found:
All rights reserved. Printed in the United States of America. This publication is protected by copyright, and permission must be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form or by any means, electronic, mechanical, photocopying, recording, or likewise. For information regarding permissions, write to: (...)
Why is it so easy to find these PDF versions, and why is no action being taken here?