For a cubic polynomial of the form \( ax^3 + bx^2 + cx + d \), the product of its zeroes \( \alpha, \beta, \gamma \) is given by the relation:
\[
\alpha \beta \gamma = -\frac{d}{a}
\]
For the polynomial \( x^3 - 3x^2 + x + 1 \), the coefficients are:
\( a = 1 \)
\( b = -3 \)
\( c = 1 \)
\( d = 1 \)
Using the formula for the product of the zeroes:
\[
\alpha \beta \gamma = -\frac{1}{1} = -1
\]
Thus, the product of the zeroes is \( -1 \).