Scott H. Murray (University of Chicago) E. A. O'Brien (Auckland University) We consider the application of the Schreier-Sims algorithm and its variations to matrix groups defined over finite fields. We propose a new algorithm for the selection of the base points and demonstrate that it both improves the performance of the algorithm for a large range of examples, and significantly extends the range of application. In particular, the random Schreier-Sims algorithm, with this enhancement, performs extremely well for almost simple groups. Current status: Reprint. Journal of Symbolic Computation 19 (1995), no. 6, 577--584.