Favorite observing books?

What are your favorites which are useful at the telescope? Below are two
mine.

The new book, Star Watch by Philip S. Harrington which focuses on finding
observing and learning about over 125 celestial objects. A no nonsense book
which contains finder charts, photos, drawings, and facts about these
objects .

The Observer's Sky Atlas by E. Karkoschka is small, loaded with charts and
easy to use in finding over 250 interesting nebulae, galaxies and stellar
clusters to magnitude 9.