The Web has been defined as the interface between Web servers and Web clients. Traditionally, HTML has been used as an intercommunication medium for the Web. Web-Based Information Systems (WBISs) is the most general class of Web sites being fully distributed, platform-independent and having a hypertextual user interface. XML is emerging as a new standard for data exchange and data representation on the Internet. The W3C Consortium is responsible for the development of standards for the Web. In this dissertation we have showed how XSL and XPath could be used to meet the query requirements of SWISS-PROT, which is a WBIS. We have showed that XSL offers some level of extensibility as a query language for SWISS-PROT, but if queries were to be extended to a high level of complexity XQuery would be more appropriate to use since using XSL for this purpose includes hand-coding of for-loops and if-statements. Another problem is related to maintenance. Updating the structure of the XML source would include updating hand-coded for-loops and if-statements. There is still no recommendation available for XQuery at the W3C Consortium. Considering other factors of information management, we have showed that XSL and XPath would play a significant role in displaying and formatting information in SWISS-PROT. This would though require that Web browsers in SWISS-PROT have standardised support for XML.