With the adult coloring book trend still on the rise, its no surprise that a recent slew of sci-fi and comic book-based items have started to crop up, especially in areas that thrive off an entire collector's market.

Even if The Doctor Who Coloring Book is only the latest from a fad that might fade as suddenly as it shot to popularity, it can stand on it's own as a unique item of memorabilia. It promises (and delivers) "planets, galaxies, villains, heroes, the Doctor, the Tardis and the time vortex," but it also gives us something more: a touching tribute to more than five decades' worth of Doctor Who. And even though The Doctor Who Coloring Book is being marketed to teens (the drawings might be a bit too complex for the average preschool- or kindergarten-aged Whovian), it's sure to delight any fan of the show that can color within the lines.

Created by Penguin imprint Price Stern Sloan, the illustrations in The Doctor Who Coloring Book, like the Tardis, are an intricate set of whimsical gears and bolts. This is probably no mere coincidence: the imagery featured throughout the book speaks to one of the main themes of the series: how each individual by providence of being alive contributes to the unknowable beauty of the universe. But there's a practicality to this, too. The intricacy of detail leaves a lot of room for not just vibrant color, but a chance to add a spark of originality to each picture while maintaining the integrity of the image - or, on the flip side, to completely go all out and make the drawings your own, or stick strictly to the look of whatever it is you're coloring.

Concentricity also seems to be a theme, whether it be from a standard circle pattern to jamming in the likenesses of later or earlier doctors into the silhouetted profile of another, really bringing to home the idea of the doctor as a sort of intergalactic matryoshka doll - or, as Matt Smith's Eleventh Doctor put it so poignantly before his regeneration into Peter Capaldi's Twelfth Doctor:

"We all change, when you think about it, we're all different people; all through our lives, and that's okay, that's good, you've gotta keep moving, so long as you remember all the people that you used to be. I will not forget one line of this, not one day, I swear. I will always remember when The Doctor was me."

While many recent fans of the series might be more interested in the latter regenerations of the Doctor from the 2005 series reboot, the coloring book keeps the show's OG fan base in mind. The pages feature all 12 versions of the character, from William Hartnell's initial iteration of the mysterious, curmudgeonly-yet-lovable First Doctor, which premiered in 1963, to the latest regeneration of the character, Capaldi's blunt, pragmatic Twelfth Doctor, which took on the mantle of the series in December 2013. (And for hardcore fans: even the War Doctor is there.)

Much like "all the people" that the Doctor "used to be" crop up in the coloring book, so do the other tried and true heroes of the series: the Doctor's companions. Fan favorites from the First Doctor's first companion, granddaughter Susan Foreman (played by Carol Ann Ford) to Rose Tyler (Billie Piper) make their own string of cameos.

As indelible as the Doctor's fellow travelers are, so, too, are the show's villains, which are possibly more celebrated in the book than any character the Doctor in any form would call his friends: Daleks, Cybermen and Weeping Angels alike are given their own one-off pages. To quote another regeneration, the Ninth Doctor: "Everybody lives!"

Another key factor in what makes The Doctor Who Coloring Book an excellent item for any collector of show paraphernalia is the inclusion of some of the show's most unforgettable quotes. The one-liners, found on the back of each page, are paired accordingly with every image - a choice that avoids an aesthetic detraction but adds to the overall meaning of any given illustration. And with a matte cover and French flaps, it's equally easy to picture The Doctor Who Coloring Book on a coffee table or a craft room.

An added bonus: the coloring book features a visual scavenger hunt with characters, places and things for you to spot, adding another layer of fan-based fun to the whole experience.

The Doctor Who Coloring Book is available for purchase via Amazon now.

Check out some of the illustrations featured in The Doctor Who Coloring Book below.