This research topic is very important in machine learning and a first step for all kinds of machine learning algorithms. Having a robust representation definitely plays a vital role for good performance/accuracy.
Recent progress of representation learning is using deep architecture (normally referring to deep learning). Here I collect some of very good papers worth reading:
1) Representation Learning: A Review and New Perspectives (Yoshua Bengio et al., 2014)
2) Deep Learning of Representations for Unsupervised and Transfer Learning (Yoshua Bengio et al., 2012)
3) ...
