Not sure if it's still in print but The Instrument Flight Training
Manual by Dogan was really good when I was getting my ticket.

HTH

In my opinion, Dogan's book is one of the best. It was an may still be the
primary text for the 10 Day Instrument Rating Courses, and I've personally
used it as the primary text for several instrument ground schools. It gives
real world scenarios at the beginning of each chapter that pull the student
into the meat of the subject in a way that he understands.

My requirements for instrument ground instruction are that the student have
3 different text books. The FAA Instrument Flying Handbook, not solely
written by the FAA, many of the authors you will see listed here have
contributed, making it much easier to read than previous versions. The
second is Dogan's Instrument Flight Training Manual, this was used for
homework reading and class discussions. The third was Gleim's Instrument
Course, which we followed after lectures and demonstrations to prepare the
student for the knowledge exam. I also strongly encouraged the students to
find another text from an author that they personally found easy to read and
understandable. This was used to re-confirm what was taught in class, bring
new points of view to different subjects, and to give the student an
additional source of reference in areas where the other text may have fallen
short. Instrument students should already own a copy of the FAR/AIM. The
AIM will be a constant reference during your instrument training.

Bob Gardner's The Complete Advanced Pilot is a great book that can also be
used as a instrument students primary text. It reads well, is easy to
follow, and is very comprehensive. Many of my students have chosen Bob's
book as their personal reference. Bob is a real "one of us", often in the
news groups helping students and pilots answer questions. His books read
from the point of view of another pilot, drawing on his real life experience
and real life situations. You will find non of the lofty "man on high" or
know it all attitudes that some authors inflict on us.

Bill Kershner's The Advanced Pilots Flight Manual is another great book, and
with Bills background in engineering, he places extra emphasis on the
mechanics and math behind instrument flight.

Eckalbar's book, IFR: A Structured Approach, is written from a multi engine
pilots point of view, and primarily stresses the pitch and performance style
of instrument flying. It's a great book for an advanced pilot, or for a
pilot who, with the assistance of his CFII, want to develop a very
structured method of instrument flying. My opinion is that this is a great
book for continued training after you've mastered the basic instrument
skills. It's one of my favorites to grab off the shelf and re-read.

Sample many, buy the books that you enjoy reading.

Jim