The logical title to be the first of the martial arts masterworks would have been the longest running and by most accounts the best, Master of Kung-Fu. However, that title has licensing issues because of the use of trademarked characters like Fu Manchu. As a result we must make do with Iron Fist introduced in Marvel Premiere 15. This book is a middling 244 pages which seems a little short for 13 issues (Marvel Premiere 15-25, Iron Fist 1-2) but is a reflection of the low page count of 1974-1975.
The first part of the book (MP 15-22) is the origin arc which is very fast paced and features a bevy of writers and artists. This is usually a recipe for mediocrity but surprisingly the arc holds up very well, as good as the second part, in my opinion. The second part is written by the celebrated Chris Claremont of X-Men fame and is slower paced and more intricately plotted. The last three issues features art by Claremont's X-Men collaborator, John Byrne. The arc has not played out by the end of the book but is very well done.
There are no extras besides the standard creator biographies.
Curiously, Marvel's showcase title, Marvel Premiere has now been masterworked through issue 25 in various Warlock, Dr. Strange, and Iron Fist books.
In short, highly recommended despite the creator merry-go-round in the first half.