This report presents the formulation, validation, and user's manual for the computer program BL2D. The program is a fourth-order-accurate solution scheme for solving two-dimensional or axisymmetric boundary layers in speed regimes that range from low subsonic to hypersonic Mach numbers. A basic implementation of the transition zone and turbulence modeling is also included. The code is a result of many improvements made to the program VGBLP, which is described in NASA TM-83207 (February 1982), and can effectively supersede it. The code BL2D is designed to be modular, user-friendly, and portable to any machine with a standard fortran77 compiler. The report contains the new formulation adopted and the details of its implementation. Five validation cases are presented. A detailed user's manual with the input format description and instructions for running the code is included. Adequate information is presented in the report to enable the user to modify or customize the code for specific applications. Iyer, Venkit Unspecified Center APPLICATIONS PROGRAMS (COMPUTERS); AXISYMMETRIC FLOW; BOUNDARY LAYER FLOW; COMPUTATIONAL FLUID DYNAMICS; TWO DIMENSIONAL BOUNDARY LAYER; USER MANUALS (COMPUTER PROGRAMS); BOUNDARY LAYER TRANSITION; COMPUTATIONAL GRIDS; FORTRAN; HYPERSONIC BOUNDARY LAYER; SUBSONIC FLOW; SUPERSONIC BOUNDARY LAYERS; TURBULENCE MODELS...