February 17, 2010 — If a book is worth reading, it's worth buying too.

If you're reading a book primarily to gain value from it(as opposed to reading it for pleasure) you should always buy it unless it's a bad book.

The amount of value you can get from a book varies wildly.

Most books are worthless.

Some can change your life.

For simplicity, let's say the value you can derive from any one book varies from 1 cent to $100,000(there are many, many more worthless books than there are of the really valuable kind).

The cost however, does not vary as much. Books rarely cost more than $100, and generally average to about $15.

You shouldn't read a book that you think will offer you less than $100 in value. Time could be better spent reading more important books.

So let's assume you never read a book that gives you less than $100 in value. Thus, the cost of a physical copy of the book **is at most 15% (using the $15 average price) of the value gained**.

Would owning the book help you extract 15% more from it?

It nearly always will.

When you own a book, you can take it anywhere.

You can mark it up.

You can flip quickly through the pages.

You can bookmark it.

You can easily share it with a friend and then dicuss it.

If these things don't help you get 15% more out of that book, I'd be very surprised.

Where it gets even more certain, is when you read a really valuable book--say a book offering $1,000 of value. Now you'd only need to get 1.5% more out of that book.

The investment in that case is a no brainer.