LJ Cohen is the author of eight novels across the science fiction and fantasy genres, including the Halcyone Space series—Derelict (2014; Library Journal self-e select title and book of the year), Ithaka Rising (2015), Dreadnought and Shuttle (2016), Parallax (2017), and A Star in the Void (2018)—and the Changeling's Choice series—The Between (2012) and Time and Tithe (2015)—as well as the standalone novel Future Tense (2014), all from Interrobang Books.

Her short stories have appeared in various anthologies. Her most recent short story, "Persistence of Memory," appears in the first volume of Unfit Magazine. LJ's poetry has appeared in numerous ezines and journals including Amaze: The Cinquain Journal, Gunpowder River Poetry, Loch Raven Review, Poems Niederngasse, Stirring: A Literary Collection, The Writer's Hood, World Haiku Review, and New Solutions. She is co-editor, with Talib S. Hussain, of Pen-Ultimate: A Speculative Fiction Anthology (Interrobang Books, 2013) and Pen-Ultimate II: A Speculative Fiction Anthology (Interrobang Books, 2017).

Her professional writing includes multiple chapters in Chronic Pain Management for Physical Therapists (Butterworth-Heinemann, 1997), "The behavioral role of physical therapy in pain management" (Harriët Wittink, MS, PT, OCS, and Lisa Janice Cohen, MS, PT, OCS, in Current Review of Pain, 1998, Volume 2, Issue 1, pp. 55-60), and "Chronic Pain" (Physical Rehabilitation, 5th edition, FA Davis, 2007). After a twenty-five year career in physical therapy, LJ now uses her clinical skills to injure her characters.

LJ was among the first wave of indie writers to qualify for SFWA membership. Her publishing imprint is Interrobang Books. She is also active in Broad Universe. Her blog, Once in a Blue Muse, has been active since 2005, when dinosaurs roamed the earth in internet reckoning (ljcbluemuse.blogspot.com).

She splits her time between the Boston area and StarField Farm in central Massachusetts, where she lives with her spouse and their two dogs.