Darwin consolidated a lifetime of work in 'On the Origin of Species', compiling his discoveries from the voyage of the Beagle, his experiments, research and correspondence. The book was written for non-specialist readers and attracted widespread interest upon its publication. As Darwin was an eminent scientist, his findings were taken seriously and the evidence he presented generated scientific, philosophical, and religious discussion. The debate over the book contributed to the campaign by T.H. Huxley and his fellow members of the X Club to secularise science by promoting scientific naturalism. He argued for the transmutation of species over time by the process of natural selection. His work laid the foundation of evolutionary biology, though when it was published it caused tremendous religious and philosophical debates. Darwin's work is still seen by many people to oppose Christian beliefs.