Jackson's novel tells of a divorce lawyer, someone who views her calling as breaking up families, discovering she has two siblings she doesn't know she has and finding herself in the position of struggling to bring a family together. Brown writes about a middle-aged postmaster who falls in love for the first time in his life and seems to do everything wrong, yet somehow manages to do everything right.
Other notable novels read this year (none of them actually published in 2017) included Tracy Chevalier's The Last Runaway, about a young Quaker woman who settles in Ohio in the mid-1800s and becomes involved in the Underground Railroad while falling in love with a man trying to round up runaway slaves; Marilynn Robinson's Gilead, about a dying pastor's attempt to explain himself to his very young son; and Anthony Trollope's Cousin Henry, about a lost will and characters who take moral stands for less than moral reasons.
Which is the best of these? I'd say Lamb in Love, with The Last Runaway a close second.
As for nonfiction reading, I had a good time with biographies in 2017. The best was Michael Korda's Clouds of Glory about Robert E. Lee, but Coolidge by Amity Shlaes, Mr. Strangelove by Ed Sikov (about actor Peters Sellers) and Ike's Bluff (about the Eisenhower presidency) were also first-rate.
Other nonfiction works that impressed me were The Road to Character by David Brooks, Sanctuary of Trees by Gene Logsdon, Truth & Beauty by Ann Patchett and The Better Angels of Ourselves by Steven Pinker.