  Myriad articles are devoted to Mertens's theorem. In yet another, we merely
wish to draw attention to a proof by Hardy, which uses a Tauberian theorem of
Landau that "leads to the conclusion in a direct and elegant manner". Hardy's
proof is also quite adaptable, and it is readily combined with well-known
results from prime number theory. We demonstrate this by proving a version of
the theorem for primes in arithmetic progressions with uniformity in the
modulus, as well as a non-abelian analogue of this.
