Can anyone recommend good books, articles or essays that introduce machine learning?

Norvig is easier to read - larger pages, more diagrams, better writing, and you know where you are better - and fresher material.

the Norvig book is an AI book, not an ML book.

I'd recommend the Norvig book which covers everything Mitchell does (IIRC) except 'Probably Approximately Correct' (PAC) learning.

Artificial Intelligence A Modern Approach SE, by Stuart Russell and Peter Norvig.

I would also suggest Elements of Statistical Learning

Bishop's book is excellent.

Christopher Bishop's one I'd look at

I really like the recent (Oct 2007) book: Pattern Recognition and Machine Learning by Christopher M. Bishop

I'll second this recommendation - I bought the printed copy, and I'm constantly going to it for reference.

Information Theory, Inference and Learning Algorithms by David MacKay is excellent, and freely available online.

Segaran's "Programming Collective Intelligence", mentioned above, is the best first bet, primarily because it's fun. And the code is good.

I found the "Programming Collective Intelligence" book to very readable and practical, but very light on the theoretical foundations

The "Programming Collective Intelligence" book is pretty good in terms of a practical introduction to a variety of techniques.

"Programming Collective Intelligence"

Programming Collective Intelligence by Toby Segaran for a practical approach in Python.

I wish they'd make a new edition; but, probably, the field is moving too fast.

Sutton and Barto's book on reinforcement learning is available online

between Norvig and Mitchell, Norvig has 138 pages on learning vs Mitchell's ~390

If you can read and understand Mitchell's book, you will have a very good foundation for understanding modern ML techniques.

I agree on the Mitchell book.

"machine learning"

Machine Learning by Tom Mitchell for a serious academic book.

I've got a copy of the Witten ML book ("Data Mining: Practical Machine Learning Tools and Techniques"), but to be honest I haven't gotten much from it yet

try: Data Mining: Practical Machine Learning Tools and Techniques (Second Edition)

"Data Mining: Practical Machine Learning Tools and Technique"

I would recommend Tan's Introduction to Data Mining

As well as Duda, Hart, and Stork's Pattern Classification