This book has been written for to the graduate and postgraduate students who have opted for the Organic Chemistry study course. This book is prepared especially for those students who are preparing for the NET-JRF-CSIR, SET,SLET, GATE Chemical science. Lots of question come in the competitive exam from pericyclic reactions, it can be prepared according to that point of view which help the student and the references or most of the reaction taken from the standard books Carruthers and Clayden books. This book includes all concept of pericyclic reaction like electrocyclic, Diels-Alder reaction, Claisen reaction, [2,3] Sigmatropic reaction and [3,3] Sigmatropic reaction covers reaction in which general methods of preparations, synthetic applications and mechanism is discussed in details with different sets of examples. The large numbers of problems with solutions have been included at the end of each topic and covering the questions asked in different universities and competitive examinations like CSIR-NET or GATE. The pericyclic reaction is the most important branch of chemical science which wide exploited in the architecture of organic molecules with high biological sign.