Best rationalist philosophy books according to redditors

This is Stroud's book on dealing with metaphysical subjects. It doesn't directly deal with the problem of free will, but I HIGHLY recommend you read this book because it allows you to gain insight into what a lot of books and papers are missing, namely, what I was talking about 'coherence' or an 'unmasking explanation' (his terminology, actually):
http://www.amazon.com/Quest-Reality-Subjectivism-Metaphysics-Colour/dp/0195151887

Searle's book on Rationality. What I had paraphrased is actually in this book (... I think, it's been a little while since I read it), but I know he addresses the problem of free will since it's important to him in tackling rationality:
http://www.amazon.com/Rationality-Action-Jean-Nicod-Lectures/dp/0262692821

Here's a book that has a ton of papers from prominent philosophers in the field. This actually gives a good overview of the whole debate. I recommend P.F. Strawson's Essay, Wallace's Essay, and ... I forget the other one. IIRC, there are essays by Lewis and van Inwagen if you're really into logic approaches:
http://www.amazon.com/Free-Will-Oxford-Readings-Philosophy/dp/019925494X

It's only a few but I hope that helps~

Massimo Pigliucci is fine from what I've seen. He's also an academic philosopher, but writes a lot of public stuff.

Nigel Warburton and David Emonds are now full-time public philosophers and I enjoy the things they do: from their short books to the Philosophy Bites podcasts and so on.

There are also a number of academic philosophers who have written public pieces, even if that's not the majority of what they do. Al Mele has a recent book on free will, Michael Lynch has one on epistemology in the internet age and the role of reason in democracy. There are certainly others I'm forgetting.

You can also check out Aeon's essays for dozens of good, ~3000 word pieces by professional philosophers aimed at a wide audience and on a variety of subjects.

EDIT: looking at your specific topics I would suggest checking out Lynch's In Praise of Reason and Pigliccui's A Short History of Truth. The former is very good; I haven't read the latter, but there's not a ton of good books on truth that are easy. You might also look at Simon Blackburn's Truth: A Guide.

https://www.amazon.com/dp/B004TOPI7I/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1#customerReviews

The Philosophy of Spinoza by Joseph Ratner.

This should work. I've read part way into it. While the language is a little dense and archaic in places, it's still readable and strikes a nice balance between substance and being accessible.

The Philosophy of Spinoza is an abridged version of Spinoza's works and one of the few to break it down into something approaching understandable language for the lay reader. It removes the geometric proofs and gives you the key points. It is a substantial book though, and gives you a solid working knowledge of what Spinoza was about.

It's also free. :)