[nekokami]

Oh, well, Tom Riddle's diary seems as appropriate. But I thought you wanted older references. If we're talking about contemporary works, I'd submit these from Garth Nix's Lirael:

In the light, she realized it wasn’t bound in fur or hide, but had some sort of closely knitted cover over heavy boards, which was very peculiar indeed.

She picked it up and flicked it open to the title page, but even before she read the first word, she knew it was a book of power. Every part of it was saturated with Charter Magic.

There were marks in the paper, marks in the ink, marks in the stitching of the spine.

The title page said merely In the Skin of a Lyon. Lirael turned it over, hoping to see a list of contents, but it went straight into the first chapter. She started to read beyond the words “Chapter One,” but the type suddenly blurred and shimmered. She blinked, rubbed her eyes, but when she looked again the page had the heading “Preface,” though she was sure it could not have turned. She turned back, and there was the title page again.

Lirael frowned and flipped forward. It still said “Preface.”

It was The Book of the Dead. A small volume, bound in green leather, with tarnished silver clasps. Leather and silver laden with protective magic. Marks to bind and blind, to close and imprison. Only someone with an innate talent for Free Magic and necromancy could open the book, and only an uncorrupted Charter Mage could close it. It contained all the lore of necromancy and counter-necromancy that fifty-three Abhorsens had gathered over a thousand years—and more besides, for its contents never stayed the same, seemingly altering at the book’s own whim.

As could be expected of a Second Assistant Librarian, she reached for the book first, her fingers touching the silver clasp that held it shut as she read the title embossed in silver type upon the spine: The Book of Remembrance and Forgetting.

Lirael undid the clasp, feeling Charter Magic there, too, noting the marks that chased each other across the silver surface and deep in the metal itself. Marks of binding and closing, burning and destruction.

But the clasp was open by the time she realized what the marks were, and she stood unharmed. Carefully, she turned back the cover and the title page, the crisp, leaf-thin paper turning easily. There were Charter marks inside the pages, put there at the time of the paper’s making. And Free Magic, constrained and channeled into place. Magic of both kinds lay in the boards and leather of the cover, and even in the glue and stitching of the spine.

Most of all, there was magic and power in the type. In the past, Lirael had seen similar, if less powerful, books, like In the Skin of a Lyon. You could never truly finish reading such a book, for the contents changed at need, at the original maker’s whim, or to suit the phases of the moon or the patterns of the weather. Some of the books had contents you couldn’t even remember till certain events might come to pass. Invariably, this was an act of kindness from the creator of the book, for such contents invariably dealt with things that would be a burden to recall with every waking day.