This book has now been extensively revised and considerably enlarged. It now contains most of the topics concerning design and analysis of experiments. Presentation is mainly based on intuition and common sense using minimum mathematics. There are quite a number of new and yet unpublished results in the edition. The methodology has been evolved for providing efficient algorithms for writing computer programs and complete programs for many of the techniques are now included in the book. Each of the existing chapters has been extended by several numerical examples and new material to make the book self contained. This edition has been enlarged by including four more chapters covering main effect plans, several series of new designs, switch over designs and dialled crossing plans. A chapter on computer programs is an interesting and useful addition to the revised edition. Complete programs of composite nature are presented without redundant commands, camouflaging and any motive of secrecy so that the readers can have a feel of actual sequencing of commands constituting programs for problems of which the algorithm is known to them. Each program is supported by liberal notes needed for its execution.