I'd read anything Lawrence Block wrote, cereal boxes, if necessary--that's how much of a fan I am. His only competitor in a narrow field is Donald Westlake, and Block is a tad or so better.
The plot of "Long Line" involves a tontine, a club of disparate men who meet once per year to see who has died. Unlikely? Yes, but bear with it. After a time it appears that the members are dying faster than normal, and Scudder is hired to find out why. It's been done before with different twists (e.g., Agatha Christie's "And Then There Were None"), but it's not bad. I would add only that the first pages were a bit tedious--until Scudder takes the reins. Then the book moves. But it's not the plot that makes this book worthwhile.
Block's characters, the ambience of New York City and the dialogue, especially the latter, are what carry this. Block's people are full of contradictions. Too often writers invent characters who stay on a narrow track, but never Block. For example, unlicensed detective Scudder is devoted to his main squeeze, but now and then he strays. His main squeeze is an ex-call girls who has an artsy Manhattan shop and an eye for what is "in" with the artsy buyers. She can sell "paint by the number" works for hundreds of dollars if the painting is in an expensive frame. Block's African American friend talks jive and straight, and the reader is never sure which is his real voice.
Block invents some streets and byways of the City, but that causes no harm. I wouldn't nitpick that. Block's city is very much alive. His most obvious talent, however, is in writing dialogue. No one does it better. It's funny. It's real. There are very funny throwaway lines.
While this is not my favorite Block novel, it's a worthwhle read--and a good deal better than most other crime novels.