Mobile friendly website & responsive web design the same thing?

Is a mobile friendly website & responsive web design the same thing?

This could be one of those questions that will form strong options, mine will be just one of those.

Originally when learning about responsive web design I started with reading Ethan Marcotte’s book Responsive Web Design that then lead me to read Mobile First by Luke Wroblewski.

Expand on the two here, what makes them different and where they overlap. Ideally down the track they will merge into one.

Mobile first will look at load times as opposed to responsive web design which may not factor in load times a priority for mobile devices over say desktop with a high speed internet connection.