The earliest use of business cards were in parts of England at the beginning of the 17th century. Merchants drew maps on the back of pieces of paper to help people find their establishments. It’s not difficult to understand how they evolved from that point.
The modern business card is, in some cases, a work of art. The quality of ink, design, 3D images, and more can really attract attention. But in the end it is the basic information the customer wants – who you are, name of your company, your title, and contact information. However the true value of a business card is the gesture of exchanging the card with someone. It is entering into an informal relationship that might be the most important one of your business career.
Now think about that gesture and imagine if you gave someone your book. What impact might that have on the relationship? What does a book written by you – say – about you? I would suggest it deepens the exchange, develops a stronger bond, and puts you in a special category.