The association of British Dispensing Opticians Ltd. 1984,1994. 4th edition (reprinted 1994). Foreward by J.R.S. Baker. The original book was written in the hope that it might help to fill the gap existing in ophthalmic literature in the field of spectacle lens theory. Whilst written primarily for students of dispensing optics, the text has been made intensely practicalin the hope that it may also be of service to technicians in the ophthalmic prescription industry. In this fourth edition, the sections on spectacle lens design using the computer havebeen completely rewritten to reflect modern methods of computation.