update readme with the defunct message

README.md

@@ -96,8 +96,12 @@ text in 20 different languages. The dataset comes in preprocessed format, so tha
 formatting boilerplate has been removed.
 
 #### Gutenberg and Books3
-The PG19 subset of the Gutenberg Project and Books3 datasets are downloaded from Huggingface. After downloading, we use 
-simhash to remove near duplicates.
+
+
+<div class="course-tip course-tip-orange bg-gradient-to-br dark:bg-gradient-to-r before:border-orange-500 dark:before:border-orange-800 from-orange-50 dark:from-gray-900 to-white dark:to-gray-950 border border-orange-50 text-orange-700 dark:text-gray-400">
+  <p><b>Defunct:</b> The 'book' config is defunct and no longer accessible due to reported copyright infringement for the Book3 dataset contained in this config.</p>
+</div>
+
 
 #### ArXiv
 ArXiv data is downloaded from Amazon S3 in the `arxiv` requester pays bucket. We only keep latex source files and