The recent advancement of computer technology makes reservoir simulations feasible in a personal computer (PC) environment. This manual provides a guide for running BOAST-VHS, a black oil reservoir simulator for vertical/horizontal/slant wells, using a PC. In addition to detailed explanations of input data file preparation for simulation runs, special features of BOAST-VHS are described and three sample problems are presented. BOAST-VHS is a cost-effective and easy-to-use reservoir simulation tool for the study of oil production from primary depletion and waterflooding in a black oil reservoir. The well model in BOAST-VHS permits specification of any combination of horizontal, slanted, and vertical wells in the reservoir. BOAST-VHS was designed for an IBM PC/AT, PS-2, or compatible computer with 640 K bytes of memory. BOAST-VHS can be used to model a three-dimensional reservoir of up to 810 grid blocks with any combination of rows, columns, and layers, depending on the input data supplied. This dynamic redimensioning feature facilitates simulation work by avoiding the need to recompiling the simulator for different reservoir models. Therefore the program is only supplied as executable code without any source code.