  We show that the Wyman's solution may be obtained from the four-dimensional
Einstein's equations for a spherically symmetric, minimally coupled, massless
scalar field by using the continuous self-similarity of those equations. The
Wyman's solution depends on two parameters, the mass $M$ and the scalar charge
$\Sigma$. If one fixes $M$ to a positive value, say $M_0$, and let $\Sigma^2$
take values along the real line we show that this solution exhibits critical
behaviour. For $\Sigma^2 >0$ the space-times have eternal naked singularities,
for $\Sigma^2 =0$ one has a Schwarzschild black hole of mass $M_0$ and finally
for $-M_0^2 \leq \Sigma^2 < 0$ one has eternal bouncing solutions.
