CAPTION: David Tennant, center, has bid farewell to his role as the 10th Doctor in “Doctor Who.” His co-stars in his final two-part episode, “The End of Time,” are Bernard Cribbins, left, and John Simm.

Doctor Who: The Complete Specials (Great Britain, BBC, 5 Blu-ray discs, NR, 311 min.). After four years as the 10th Doctor in the long-running British series, David Tennant has retired from the TARDIS. Taken as a whole, and I have seen at least half of the total episodes, I’d say that, without a doubt, Tennant was the best Doctor and he will be sorely missed.

In a recent interview on “The Graham Norton Show,” Tennant said he was leaving while the show was on top, while he still enjoyed it. That he did not want it to reach the point where he’d say, “Oh no, not another show about the Daleks.” And he already has made a pilot for a potential NBC series in which he plays a lawyer with stage fright, who thus coaches his clients on how to be their own lawyers.

Rather than a full season, writer Russell T. Davies and the BBC offered us five specials, here collected and presented in Blu-ray format with excellent sound and visual crispness. Two have been previously reviewed in this column, “The Next Doctor” (the sole episode up-converted from standard DVD) and “Planet of the Dead.” The former is set at Christmas 1851, with Cybermen stalking Victorian London and one resident believing he is The Doctor. The latter has a London bus travel through a wormhole in an underpass to a desert world.

The final three episodes are the best, and are very much tied together. In “The Waters of Mars,” The Doctor visits the crew of Mars Base One in 2059, only hours before he knows they will be mysteriously destroyed. The Doctor was to confront the realization that this is one time he cannot come to the rescue, because it would have deadly consequences for Earth. There is an alien life force, mostly made up of water, that is taking over the crewmembers’ bodies and has taken the Earth as its goal. The ending is quite sad as, after The Doctor feels he has done the right thing, it backfires on him. Finally, there is the two-part “The End of Time,” with The Master (John Simm) back to take over the Earth by turning everyone into a copy of himself. There also is a group of Time Lords, led by the Lord President (former-James Bond Timothy Dalton), who want to turn Earth into a version of their destroyed home world. The Doctor is helped by Donna Noble’s grandfather Wilf (Bernard Cribbins) – all of Donna’s memories of her time as The Doctor’s companion had been wiped away previously. And it is in saving Wilf that The Doctor gives up his current life.

The show ends brilliantly and with high emotions, as The Doctor visits all the important people in his life, including companion Rose before she met him, doing a last few good deeds before regenerating.

Extras include the “Doctor Who Confidential” for each episode (with slight contractual edits for “The End of Time” one); 17 minutes of deleted scenes from all four stories with introductions by writer Davis; Tennant’s video diaries of his final days; a visit to Comic-Con; and audio commentary on “The End of Time” by Tennant and director Euros Lyn, with Catherine Tate (Donna) on part one and Simm on part two. Overall grade: 3.75 stars

Doctor Who: The Twin Dilemma (Great Britain, 1984, BBC DVD, NR, 99 min.). Speaking of The Doctor’s regeneration, this story, the 137th in the original series, was the first time Colin Baker stepped into the role as the sixth Doctor. He would last until 1986. With his regeneration, The Doctor is confused, occasionally angry and overall acting strangely. At one point, he even tries to kill companion Peri (Nicola Bryant). Meanwhile, two mathematical genius twins, Romulus and Remus, are kidnapped from Earth by someone who later turns out to be Time Lord Asmael (Maurice Denham). They are being taken to the planet Jaconda, which has been taken over by giant slugs – the lead one looks like an insect with an owl’s face (weird combination). The sets are cheap, the costumes tacky and the aliens silly, but the story is OK, albeit a bit stretched to fill four episodes. This is universally regarded as one of the worst episodes in the series history, though.

DVD extras are plentiful and include audio commentary by Baker, Bryant and Kevin McNally (he plays shot-down pilot Hugo); a discussion of costumes by Baker and comedian Amy Lame; a BBC interview with Baker and Bryant; an interview with opening sequence designer Sid Sutton; a 17:46 look at the Doctor Who comic book; and a photo gallery. Overall grade: 2 stars

Also recently released from the Doctor Who series are 1964’s “The Keys of Marinus,” featuring William Hartnell in the series’ fifth adventure (an island of glass is surrounded by a sea of acid; the island contains a machine  that can remove evil from the minds of entire population, but its keys have been scattered and hidden); and 1969’s “The War Games,” featuring Patrick Troughton in the series’ 50th adventure (the TARDIS materializes amidst the trench warfare and poison gas, and The Doctor must turn to the Time Lords for help).

Rating guide: 5 stars = classic; 4 stars = excellent; 3 stars = good; 2 stars = fair; dog = skip it

Additional reviews are available online at villagesoup.com and include the romance “Love Happens,” “Saw VI,” a new edition of the classic “The Wolf Man” and the 1990-91 series “She-Wolf of London.”