BIAS is a ZX Spectrum assembler which interacts with the BASIC system to provide a flexible programming environment. It contains several nonstandard features such as the inclusion of split-IX instructions and Spectrum floating point calculator operations. It is fully relocatable. Full instructions and a binary are contained within the zip file. The binary consists of just the assembler code. This can be loaded into a Spectrum emulator which supports TAP files by selecting bias_bin.tap and typing the BASIC instruction LOAD "bias.bin" CODE nnnnn. Two code files in TAP file format are also provided for conversion from other assemblers. "gens2pro" is for Hisoft GENS assembler source files, and "asm2pro" is for EDTASM source files. Both files load in at 64000 and have the same calling sequence: PRINT USR 64000,start_of_text The result will be a program which, with some editing to remove the assembler options, is suitable for input to BIAS. Ian Collier imc@comlab.ox.ac.uk