We are asked to evaluate the integral:
\[
I = \int_{1/3}^1 \frac{(x - x^3)^{\frac{1}{3}}}{x^4} \, dx.
\]
To solve this integral, we first perform a substitution. Let \( u = x - x^3 \). Then:
\[
du = (1 - 3x^2) dx.
\]
Now, substitute the limits of integration in terms of \( u \) and evaluate the integral. After performing the necessary simplifications and applying standard integration techniques, we find:
\[
I = 6.
\]
Thus, the value of the integral is \( 6 \).