We examine critically the Gambler equation and show that it is the gen
eric linearisable equation containing, as reductions, all the second-o
rder equations which are integrable through linearisation, We then int
roduce the general discrete form of this equation, the Gambler mapping
, and present conditions for its integrability. Finally, we obtain the
reductions of the Gambler mapping, identify their integrable forms an
d compute their continuous limits, (C) 1998 Elsevier Science B.V. All
rights reserved.