While in Tibet, I noticed Thangkas (brocaded paintings used as wall hangings in Buddhist temples) with 21 Taras on them. They differed from the ones with one large central figure (often of White or Green Tara). Tara is the female Bodhisattva or Buddha of compassion and is VERY highly regarded in Tibet. She is seen as radiating compassion without judgment--like the sun radiates its light on everyone. The 21 Taras have many colors. There is only 1 green Tara! There are 5 White Taras, 7 red, 2 black, and various shades of gold. The book includes a full color print (one per page) of each of the 21 in one section--probably the reason for the cost of the book. Each Tara is in an identical pose, but the aura around them differs and (more particularly) the pistils of the Utpala (lotus) flower differ completely (i.e. each is unique to its Tara).
The author of this book is, I believe, the co-author of the valuable "Lion's Gaze." He begins with a translation of the entire "Praise to the 21 Taras." Each of its 4 line stanzas addresses a different Tara. After a fairly extensive Introduction, the body of the book is devoted to a chapter on each Tara including: a line drawing of the Tara with her name and characteristic phrase, her 4-line stanza from the "Praise," then the 4 levels of meaning with phrases from the stanza in bold. They are: literal, general (generation stage), hidden (completion stage with attributes), and ultimate (completion stage without attributes). The literal is a commentary on the stanza; the general is a description of the figure of the Tara (line drawing or color plate) with explanations of the figure; the hidden is an explanation in terms of channels, bindus, etc.; and the ultimate is a Dzogchen (Great Perfection) or Mahamudra (Great Seal) analysis. Each Tara's individual mantra is then provided. The translations are simultaneous in Tibetan and English.
So, if any of these 4 levels speaks to you, this book is a treasure--especially with its wonderful color plates. It's the only book I know of in English that addresses this illuminating aspect of Vajrayana (Tibetan Buddhism). Also, the only one that provides four simultaneous analyses from four levels or perspectives within the traditions, making it a sort of Tibetan Rosetta Stone for Westerners. This is reminiscent of Kabbalists view of Pardes (the Garden) an acronym for four levels of interpretation of the Torah. As with this book, the ultimate/last level is Sod=the esoteric.