...but otherwise fairly solid.The books collected in this volume tend to be not as highly regarded as they might otherwise have been. The reason is that the "Celestial Madonna" storyline immediately follows the issues in this collection and that the stories in this collection suffer by comparison. Be that as it may, taken on their own terms most of the stories in this volume hold up fairly well.The first five issues, 120-124, feature the Avengers vs. the Zodiac which segues into the origin of Mantis. Ongoing subplots include the mental breakdown of the Swordsman, Mantis' increasing attraction to the Vision, and the latter's estrangement from the Scarlet Witch. It's fairly action packed and entertaining with a few silly plot points like the Avengers being launched into space to kill them (just blowing them up wasn't good enough?) and the Stalker being sensitive to sunlight.We then get into the first crossover with Captain Marvel with the Avengers defeating Thanos' space fleet. Captain Marvel 33 is then reprinted for no discernible reason other than Mantis appearing in a few panels. This is a complete waste of space in an Avengers Masterwork as the reader has no hope of following that intricate plot.We then get a Giant Size Avengers which reintroduces the Golden Age Whizzer back into continuity as the father of Quicksilver and the Scarlet Witch and something else. The Whizzer's fatherhood doesn't last, however.There is a one issue spotlight on the Black Panther and then we get another crossover, this time with the Fantastic Four and the Inhumans for the wedding of Quicksilver and Crystal. It isn't too bad but having just read it in Marvel Masterworks Fantastic Four 15 lessened the impact.The book closes with an interesting development with Agatha Harkness and the Scarlet Witch. The issue (and the collection as a whole) ends on a cliffhanger which kicks off the aforementioned "Celestial Madonna" storyline.The primary creative weakness is the art. Lots of pencillers and inkers and some work better than others. The art in the first few issues in this volume looks horribly rushed.Steve Englehart contributes a very informative introduction. An interesting item is the practice at the time to draw one page of art and then blow it up to a two page spread to pad the page count.Recommended to fans of the Masterworks and/or the Avengers. Not great by any means but fun and entertaining.I enjoyed this book as it contains many if not all the Avengers roster that were involved in the Avengers/Defenders War - which is a personal favorite - and contains some of Steve Englehart's best run on the title. As pointed out by Mr. Davis in his review, its collected issues are a prelude to the "Celestial Madonna" storyline, which tends to overshadow the stories collected in this book. But this volume does indeed offer some very entertaining material - which includes adventures with the Fantastic Four and the Inhumans.The crime cartel Zodiac starts it off - then the plots begins to really thicken - secret identities, romance among the ranks, pacifist priests with a secret past. Like the volume that follows, Mantis is the spotlight character. She is an interesting character with lots of back story and mystery to her - its obvious that Englehart was trying to really sell her as a powerful new addition to the Avengers roster but to think she could take Thor and Iron Man to the floor is a bit far-fetched in my opinion, given that her skills are simply martial arts - but this of course no doubt took advantage of the popularity of the martial arts/kung fu craze that was going on at the time as well. I particularly enjoyed the battles involving all three groups when going up against a certain metallic villain (... hint hint) and the growing romantic tension between Vision, Scarlet Witch, Swordsman and Mantis in the midst of Crystal and Quicksilver's wedding was well done. A side spin-off chapter involving Captain Marvel and his on-going battle with Thanos is thrown in but seems awkwardly out of place.If nothing else, Mantis' introduction to the ranks of the Avengers brings out a good degree of self reflection from some of the other team members -- Englehart spreads this theme throughout the story but never allows it to interfere with the teams mission. The artwork is top-notch - Bob Brown being particularly good - John Buscema, Sal Buscema and Jim Starlin contribute to the book as well.Vol 13 offers good Avengers action and adventure and overall a good book that I will enjoy again and again.wonderful condition!Added to my collection