The The semantic web is a big knowledge base where all applications would share and exchange knowledge. For the representation of knowledge in semantic web, ontologies are widely accepted.Semantic Web applications has brought the machines in semantic way with the help of ontologies. One of the web application named as Crawler is one of the essential component of Search engines which is widely used for searching of relevant data on internet. This book, therefore provides a new way of searching the data on internet. This book should be useful to researchers in the field of semantic web.