Donald Clark's collected critical introductions to a wide range of theorists that have some connection with learning. They are not all learning theorists as such, despite the title, though all relate to things that matter in learning and/or teaching and/or education. It's an eclectic mix that covers far more than those we normally consider to be learning theorists: the likes of Jesus and Marx are not normally grouped with the likes of Dewey and Gagne, for example.

Donald positively relishes the demolition of holy cows and many of his critiques - e.g. of social constructivistm or learning styles or Sugata Mitra  - challenge orthodoxy and commonly-held-but-mistaken beliefs in a very refreshing way. He's not always right, but he is always well-informed, thought-provoking and interesting. And, if you do disagree with anything he says, he's normally willing to engage in a reasoned debate about it on his blog - this is a million miles away from a static textbook.

For anyone wanting to get a quick, informative introduction to learning/teaching/education theories and some incisive commentary on them, as well as some excellent references to further reading, this is a brilliant learning resource.