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In this paper we develop the monotone method in the presence of upper and lower solutions for the $2$nd order Lidstone boundary value problem $$u^{\left(2n\right)}\left(t\right)=f(t,u\left(t\right),u^{\text{'}\text{'}}\left(t\right),\cdots ,u^{\left(2\right(n-1\left)\right)}\left(t\right)),0<t<1,u^{\left(2i\right)}\left(0\right)=u^{\left(2i\right)}\left(1\right)=0,0\le i\le n-1,$$ where $f[0,1]\times {ℝ}^n\to ℝ$ is continuous. We obtain sufficient conditions on $f$ to guarantee the existence of solutions between a lower solution and an upper solution for the higher order boundary value problem.