$$\lim_{x \to -\infty} \log{\left(\log{\left(x \right)} \right)} = \infty$$ $$\lim_{x \to \infty} \log{\left(\log{\left(x \right)} \right)} = \infty$$ More at x→oo $$\lim_{x \to 0^-} \log{\left(\log{\left(x \right)} \right)} = \infty$$ More at x→0 from the left $$\lim_{x \to 0^+} \log{\left(\log{\left(x \right)} \right)} = \infty$$ More at x→0 from the right $$\lim_{x \to 1^-} \log{\left(\log{\left(x \right)} \right)} = -\infty$$ More at x→1 from the left $$\lim_{x \to 1^+} \log{\left(\log{\left(x \right)} \right)} = -\infty$$ More at x→1 from the right