CNNs are great, but so prone to overfitting, thankfully that last few years have been good to the deep learning community - dropout, jitter, etc. - in combating these problems. Hopefully in the next few years more books are published to help dumb-down the material since reading a lot of these papers (in terms of trying to implement/expand/critique the material - just the history alone is interesting - hopfield nets, perceptrons, hebbian learning, ... ) is still very tough as results are difficult to reproduce
