One of the most powerful functions available in electronic books is the ability to searching the entire text of a book or books and locate words or phrases within them. Many printed books, especially scholarly books, have manual indexes at the back to help users find the specific location of the information they need. Digitized books allow readers to search every word in the content of the book.
But,
caveat emptor
: the accuracy of the search depends on the accuracy of the method used to digitize the content. Digitizing software (OCR, or optical character recognition software) is not 100% accurate at recognizing the words in the text.
And
, if only portions of the ebook are offered in full-page view, your word searches may be limited to only those pages, not the entire book. Compare mishka in Penguin's 2001 edition of
Anna Karenina
in Hathi Trust and Google Books.
Nevertheless, searching ebooks is a very powerful and potentially time-saving capability of ebooks and ebook collections.