This book is an update revision of the original Yellow Series (No 6106) book on the P-39.
Like the other MMP Yellow Series books (this is No 6129) this is a square bound, 5-1/2" x 9-1/4" (European B5 size) card cover. There are 160 pages, up from the 128 pages of the previous MMP edition. It is divided into three sections, a text section up to page 64, a close up photographs/technical manual illustrations section to page 134, and a color profile section to the end.
The first two sections, while mostly retaining the contents of the original book have some nice additions. There is an unbound foldout sheet with drawings of the P-30F and P-39Q in 1/48th scale and the latter in 1/32nd scale. As aways, make sure the foldout is part of the package when buying second hand. There are some nice additional perspective drawings of the nose detailing differences between the models. There is a very detailed Technical Description added running 11 pages. In the subtraction category the list of Soviet P-39 aces is truncated to one page. The second section has some more technical manual illustrations.
The third section is the real letdown. There has been a printing glitch somewhere along the line. The profiles largely, but not entirely, duplicate those in the first edition but some of the colors are badly off. The Olive drab has become almost black. The sand or tan colors of the desert camouflage has become greenish and the azure blue undersides a light gray. This has the look of the wrong information being provided the printer or the printer being given the wrong information rather than a "low toner" type of problem that has affected only some copies because other colors like the blue, red, white, and yellows are completely unaffected. I would appreciate hearing from others if their copies show the same effects.
Because of the above, I can't recommend the book unless the color profiles are of no real interest to you. If you have the previous edition this might not matter a great deal and you'll have to judge for yourself if the additions in the other sections are worthwhile.