"...Probably the only shared characteristic would be that these are things you can’t really get unmotivated people to grasp, but if someone is motivated, they’ll find their way in somehow. And enjoy it, after all, it is supposed to be fun, isn’t it?"

"Few days ago I have received copies of my book from Lulu.com. The prints are really impressive! If I think about it - Lulu never gave me any physical training about how to make a book cover, how to optimize the cost/readability balance etc; I only followed instructions on their website and submitted the document myself; and now I am looking at prints which are exactly what I would expect from a professional publisher."

"From a period in which geographic information systems, and later geocomputation and geographical information science, have been agenda setters, there seems to be interest in trying things out, in expressing ideas in code, and in encouraging others to apply the coded functions in teaching and applied research settings."

"Just a short word of congratulation about the open-source book project you launched yesterday; this is exactly the idea I have of the word ‘research’ (especially as a free-software advocate myself!), will try to help as much as possible."

"I've been looking at your book - I think it provides nice introductions to some important topics. I'm impressed that it's free!"

"Hi Tom. I have uploaded some comments on your book. You should check if you are able to run the code on upgraded versions of R. Otherwise fine, nice set of full-scale examples."