A Providence native, Whitman specifically responded to accusations from Rufus W. Griswold and others. One specific charge made by Griswold was responded fairly cheekily — Griswold said Poe had no friends. Whitman introduced her book, "by a friend."
It's sort of a shame now that today Whitman is only recognized for her connection with Poe — she was amongst the most famous women poets of her day and, to be honest, much of her work deserves reclaiming. At least one scholar, Brett Rutherford, agrees with me, though he still frames his book on Whitman around her relationship with Poe.
Let me sum up her relationship with Poe: She was almost his second wife. I'll give the details of their relationship closer to their wedding date in December.
After her book was published, Whitman maintained a heavy correspondence with John Henry Ingram, an independent biographer (and postal worker!) considered one of the first to punch a significant hole in Griswold's lies. And, really, it was Whitman that made Ingram's Poe biography so rich and so vital, even today.
Her relationship with Poe, her book response to Griswold, and her correspondence with Ingram make up all that she is remembered for today (quite unfortunately). A friend of mine performs as Sarah Helen Whitman on occasion, and nearly brings me to tears every time I see her.
In 1848, Whitman wrote this poem to Edgar Poe:
If thy sad heart, pining for human love,
In its earth solitude grew dark with fear,
Lest the high Sun of Heaven itself should prove
Powerless to save from that phantasmal sphere
Wherein thy spirit wandered,—if the flowers
That pressed around thy feet, seemed but to bloom
In lone Gethsemanes, through starless hours,
When all who loved had left thee to thy doom,—
Oh, yet believe that in that hollow vale
Where thy soul lingers, waiting to attain
So much of Heaven's sweet grace as shall avail
To lift its burden of remorseful pain,
My soul shall meet thee, and its Heaven forego
Till God's great love, on both, one hope, one Heaven bestow.