  In this article, I discuss the motion of $N$ point masses in non-relativistic
mechanics, when the interaction between them is purely the Newtonian
gravitational interaction, with $N$ greater than or equal to 2. The dynamical
equations of motion cannot be solved in closed form, for general initial
conditions, for any $N$ greater than 2. However, the qualitative behavior of
the solutions can be understood from general considerations. I discuss in
particular motion the three masses on a line, and the counter-intuitive case of
four masses on a line that leads to all particles escaping to infinity in a
finite time.
