Book excerpt: This book analyses the impact of web design parameters on user experience and the behaviour of website users. Website design is considered one of the key parameters of a company's Internet presentation, affecting consumer attitudes and buying behaviour. The authors examine the concept of website quality based on the identification of patterns of user behaviour in the online environment, particularly focusing on the functional and aesthetic parameters of web design and causal relationships between them. Using website traffic analysis and best practices from professionals, they describe a methodical procedure for measuring the quality of web pages and developing optimised websites.