Jeff Sackmann is the author of Total GMAT Math, Total GMAT Verbal, GMAT 111, Total GRE Math, and a variety of other test-prep resources. He also created and posts free material at the GMAT Hacks website. He has been helping students prepare for the GMAT and apply to business school since 2000.
Until July, 2005, he worked for one of the large test-prep companies, teaching classroom courses, running workshops, and tutoring. He has taught the GMAT, LSAT, GRE, SAT, and countless other specialized admissions and certification exams. In addition to teaching, he has written curriculum (including thousands of practice questions), trained teachers, and starred in instructional videos.
In his books, Jeff focuses two things: building solid content knowledge and providing extremely realistic practice material. Unlike many other resources on the market, his practice problems are virtually indistinguishable from the real thing, meaning that you are that much more prepared for the GMAT before you sit for the exam.
When he is not writing about standardized tests, you can often find Jeff on a tennis court or running through the streets of New York City, training for his next marathon.