He is currently a contributing editor of Catamaran Literary Reader in Santa Cruz, California, where he has edited such authors as Douglas Brinkley, Jonathan Franzen, Jane Vandenburgh, and Lawrence Weschler.
Other notable authors he has translated include Carlos Fuentes, Laura Esquivel, Alejo Carpentier, Louis Ferdinand Céline, and Jose Angel Valente.
An early work in this vein was The U.S.-Mexican War, which Carlos Fuentes called 'the clearest, most balanced and fully documented account' of the conflict.
It 'is a delight, an adventure, a reading and visual treat of the first order,' with Christensen uncovering 'many unimagined and unprecedented connections,' remarked David Walton in the [Cleveland Plain Dealer].
On the ForeWord Reviews website, Leia Menlove noted that 'Christensen manages to portray and connect disparate events with remarkable cogency,' in a style that 'is droll and at times hilarious.'
According to a profile of the author in the San Jose Mercury News, "with dozens of full-color illustrations, the book is a dazzling cabinet of wonders for anyone seeking knowledge about the wider world.