High Performance Web Sites Essential Knowledge for Front-End Engineers (By Steve Souders) http://oreilly.com/catalog/9780596529307
And for an intro to scalability:
Building Scalable Web Sites: Building, Scaling, and Optimizing the Next Generation of Web Applications (By Cal Henderson) http://www.amazon.com/Building-Scalable-Web-Sites-Applicatio...
High Performance Web Sites Essential Knowledge for Front-End Engineers (By Steve Souders) http://oreilly.com/catalog/9780596529307
And for an intro to scalability:
Building Scalable Web Sites: Building, Scaling, and Optimizing the Next Generation of Web Applications (By Cal Henderson) http://www.amazon.com/Building-Scalable-Web-Sites-Applicatio...