This question is from DeGroot's "Probability and Statistics" :

> 
> **Unbounded p.d.f.’s.** Since a value of a p.d.f.(probability density function) is a probability density, rather than a
>  probability, such a value can be larger than $1$. In fact, the values of the following
>  p.d.f. are unbounded in the neighborhood of $x = 0$:$$f(x) =
> \begin{cases}
> \frac{2}{3}x^{-\frac{1}{3}} & \text{for 0<$x$<1,} \\
> 0 & \text{otherwise.} \\
> \end{cases}$$
> 
> 
> 

Now, I don't know how the p.d.f. can take value larger than $1$.Please let me know the difference between the probability and probability density.