LJ Cohen is the author of seven novels across the science fiction and fantasy genres, including the Halcyone Space series — Derelict (2014, a Library Journal self-e select title and book of the year), Ithaka Rising (2015), Dreadnought and Shuttle (2016), and Parallax (2017); the Changeling’s Choice novels — The Between (2102), and Time and Tithe (2015); and Future Tense (2014).

Her short story "I Was a Teenage Alien" appears in the anthology Theme-thology: Invasion (HDWP Books, 2013; Charles Barouch, ed.). "The Forgetting" appears in the anthology Theme-thology: Day I Died (HDWP Books, 2014; Charles Barouch, ed.). “Treason’s Course” appears in the 2016 anthology Star Rebels: Stories of Space Exploration, Alien Races, and Adventure (C. Gockel, ed.). 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 of Pen-Ultimate: A Speculative Fiction Anthology (2013) and Pen-Ultimate II (2017).

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 (http://ljcbluemuse.blogspot.com). 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. She splits her time between the Boston area and central MA and lives with her family, two dogs, and the occasional international student.