How should I quote a book's name?

When writing, one often needs to quote the name of a book. How should I do it properly? I have met all of the following kinds of quotation. Which one is correct and what's the principle?

• An Introduction to Manifolds
• AN INTRODUCTION TO MANIFOLDS
• an Introduction to Manifolds
• An introduction to manifolds

Solution 1:

If you follow The Chicago Manual of Style, then publication titles are in italics, with the first letter of each word capitalized.

Short words inside the title such as a, of, the, or etc, or prepositions stay un-capitalized, regardless of length, unless they are part of an official name in the book title.

Examples:

The Basset of Bakersville Cove

Ringside Seat at the Murder

Of Mice and Men