In her outstanding fourth novel, Sabina Murray delivers a charged swathe of the past, studded with nuanced portraits and gorgeous nature writing. The eponymous Valiant Gentlemen (Grove, $27) are the Irish revolutionary Roger Casement (1864-1916) and the British sculptor Herbert Ward (1863-1919). Murray chronicles their thirty-year friendship from their meeting in the Congo in 1884 to its rupture just before Casement was executed by the British for treason. In between, Murray brings these complex, talented, and passionate men vividly to life—as she does with their families, colleagues, servants, and everyone else they encounter, a cast including Joseph Conrad, King Leopold, and Rodin. Following the protagonists from their youthful colonial adventures and budding artistic ambitions through Ward’s rise to upper-class family life and Casement’s lifelong wandering, poverty, and temporary attachments to men, Murray dramatizes many ongoing moral and socio-economic issues. Her characters’ dialogue crackles with wit and intelligence, conveying both their own perspectives on events and Murray’s insights into these figures as she traces the effects of colonialism’s callous arrogance and the blind assumptions of entrenched racism, sexism, and class discriminations. She sums up the historical abstractions in sharp, unforgettable images, from Africa’s “grass that hisses when the breeze stirs” and “the heart-chug of the steamer” on a river to the quaint Irish scene of “a donkey—picturesque with its basket and emaciated child.”