Are you Interested in a career in machine learning? Thinking where to start? While there are numerous machine learning ebooks available for free online, below you can find some niche ebooks which are free to download and give you perfect head start.
Nils J. Nilsson of Stanford put these notes together in the mid 1990s. Wait before you go on thinking its too old. While there are many advancements happened during last few years, these notes cover much of what is still considered relevant elementary material on ML. This is about 200 pages and can be read quickly to get basics right.
This book is written by Shai Shalev-Shwartz and Shai Ben-David. This is logical next step to previous book. This will delve deeper into more algorithms, their descriptions, and provide a bridge toward practicality as well.
This book has introductory text on Bayesian machine learning. It should be noted that the toolbox being referred to is implemented in MATLAB, which is no longer the default machine learning implementation language. This provides a great jumping off point for those interested in probabilistic machine learning
This book by Goodfellow, Bengio and Courville, which has a freely-available final draft copy on its official website. You would be hard-pressed to find a better resource from which to learn all about deep learning.
If you want to go one step further and want to learn about machine learning taught by ex-google team you can learn from the course available at unanth.