How is religiosity of the author relevant?
Shortly, because if someone believes in a single incorrect thing (also a quite big one that can't be overlooked), it increases the probability of him believing in other incorrect things.
The long explanation is that if the author believes in religion (something that's wrong - I know I might be wrong about it, but for reasons too long and irrelevant to write, I act as if I was certain that God doesn't exist), not only that he had tens of years of exposure to information and that didn't change his mind about it, but he actually believed in religion in the fir...
I'm considering reading the book by the title How to read a book. A friend of mine (his critical thinking is quite good, but certainly not as good as it could be, so I can't trust his opinion too much) said he has read it and that it helped him a lot. He said it had advice on reading comprehension, critical thinking ("don't automatically accept what you read") and that when people read something, they tend to forget it quite easily (and that the book addresses this issue). But he also quoted a part of the book, which said that only reading hard things will improve your reading - it might be true, but it doesn't sound intuitive to me (according to my rationalist intuition, obviously :D). Also, the book is written in 1940 and revised in 1972. Additionally, the author is religious (I think he's even highly religious). And if I remember correctly, it's not based on research - there is a quite high chance that I don't remember correctly. I checked its Amazon page, nothing said anything about research (browsed through all the low ratings to see if they complain about that, nobody did).
Should I bother reading it? If it delivers what it promises, it will obviously be so cost-effective that most rationalists should abandon reading whatever they're reading and switch to this book. But is there a version that is entirely based on research, with references or sound theory behind most claims?