  For an electron-photon collider the complete tree-level cross sections of the
reaction $\gamma e \rightarrow \nu b \bar{b} W$ are computed at center-of-mass
energies between 0.5 and 2.0 TeV, for top masses of 160 to 200 GeV and Higgs
masses between 80 and 140 GeV within the Standard Model. It is shown that most
of the $\nu b \bar{b}$ events are due to Higgs and $Z/\gamma^*$ production
(with $H, Z/\gamma^* \rightarrow b \bar{b}$ decay) while top production (with
$t \rightarrow bW$ decay) is about 50% smaller. Multiperipheral background and
interferences are small, respectively negligible, in the energy range studied.
By convoluting the basic cross sections with an energy spectrum of the
backscattered photon beam, and inserting linear collider luminosities as
anticipated in present designs, realistic $\nu b \bar{b} W$ event rates are
estimated. This results in large event rates for $\gamma e \rightarrow \nu t b$
and $\gamma e \rightarrow \nu H W$. We estimate that the CKM matrix element
$|V_{tb}|$, can be probed from the $\nu t b$ final state to an accuracy of 1-3%
at $\sqrt{s_{e^+e^-}} > 1 TeV$. Assuming an effective Lagrangian based on
dimension-6 operators we discuss the sensitivity for detecting deviations of
the HWW coupling from the Standard Model in the reaction $\gamma e \rightarrow
\nu H W$.
