Hallinan's 5th Simeon Grist detective novel "The Man With No Time" is free on Amazon today at:
The Man With No Time
This is a great series of 6 books from the 1990s. The author also has two other newer series, the Poke Rafferty books (the fifth of which is coming out in hardcover in July), and the Junior Bender books (Crashed and Little Elvises are both available on Amazon as $2.99 ebooks, and the third book, The Fame Thief, is coming out this summer).