New readers will find that Tintin's comics adventures by Hergé come in a variety of different formats, and you may not know the reading order.
Although you won't get terribly confused if you read the books out of sequence, some adventures do lead into others and characters sometimes refer to events from previous stories. The adventures are listed chronologically below.
As to format, you can go with the full-size, single "albums" or, if you're ok with the beautiful artwork being a little smaller, the more economical three-adventures-in-one volumes.
As a tie-in to the 2011 Tintin movie, there are also several "young-reader" versions of the books. In these, the adventures are intact, but supplemented with historical information that ties into the stories.
Note that the Tintin books have been in print for decades now in various editions. The links below are an attempt to connect readers to in-print copies of the books in the most common different formats. You can click the links to order the discounted books from Amazon.
Complete comics adventures of Tintin, in order:

1. Tintin in the Land of the Soviets
Sent on assignment to the Soviet Union, Tintin boards a train. . . but
after an explosion, Tintin is blamed for the bombing, and he must make
his way to the Soviet Union by stealth. Once there, he uncovers some
shocking Bolshevik secrets.
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin : Tintin in the Land of the Soviets / Tintin in the Congo

2. Tintin in the Congo
Tintin and his dog Snowy travel to the Belgian Congo to report on the situation of the country there. Once in the central African nation, the duo get into various adventures, encountering wild animals, friends and foes amongst the local black and white people, and American diamond smugglers in the employ of Al Capone.
NOTE: "Tintin in the Congo" reflects the colonial attitudes of that period in
its depiction of African people, which may cause offence to some
readers. Herge himself admitted that he was influenced by the bourgeois,
paternalistic stereotypes of the period.This entry refers to the most common version of the book. There are versions that include Herge's original, black-and-white comic strip version of the book, which he later re-drew and revised for this volume.
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin, Vol. 1 : Tintin in the Land of the Soviets / Tintin in the Congo

3. Tintin in America
Tintin and Snowy travel to the U.S. to report on a crime syndicate.
Formats:
Full-size
hardcover, softcover
Young readers edition
Combined volume:
The Adventures of Tintin: Tintin in America / Cigars of the Pharaoh / The Blue Lotus

4. Cigars of the Pharaoh
Tintin tries to take a vacation, but while on his cruise ship a mystery
unfolds! He meets Dr. Sarcophagus who leads him to the undiscovered
tomb of the Pharaoh Kih-Oskh.
Formats:
Full-size
hardcover,
softcover
Young readers edition
Combined volume:
The Adventures of Tintin: Tintin in America / Cigars of the Pharaoh / The Blue Lotus

5. The Blue Lotus
A sequel to "Cigars of the Pharoah," with Tintin continuing his struggle against a major gang of drug smugglers.
Formats:
Full-size
hardcover,
softcover
Young readers edition
Combined volume:
The Adventures of Tintin: Tintin in America / Cigars of the Pharaoh / The Blue Lotus

6. The Broken Ear
A sacred tribal statue has been stolen from the museum! Tintin and Snowy
are on the case! Clues lead them straight into the heart of the jungle.
Formats:
Full-size
hardcover,
softcover
Young readers edition
Combined volume
: The Adventures of Tintin: The Broken Ear / The Black Island / King Ottokar's Sceptre

7. The Black Island
Investigating a mysterious plane crash, Tintin discovers he's onto
something big! The case leads Tintin to Scotland, where he learns of a
monster that stalks a lonely island.
Formats:
Full-size
hardcover,
softcover
Young readers edition
Combined volume
: The Adventures of Tintin: The Broken Ear / The Black Island / King Ottokar's Sceptre

8. King Ottokar's Sceptre
Tintin meets Professor Alembick, an expert with a very rare royal seal
in his collection-the seal of King Ottokar the IV of Syldavia. Tintin
joins the professor on his trip to this foreign land, but can the
Professor be trusted?
Formats
Full-size
hardcover,
softcover
Combined volume
: The Adventures of Tintin: The Broken Ear / The Black Island / King Ottokar's Sceptre

9. The Crab with the Golden Claws
As Tintin is investigating a mysterious can of crab and a drowned
sailor, he meets Haddock, a "miserable wretch" who's being kept in ample
alcohol so his insidious first mate, Allan, can run a drug operation.
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin: The Crab with the Golden Claws / The Shooting Star / The Secret of the Unicorn

10. The Shooting Star
A meteorite collides with Earth! Tintin is part of the expedition to the
Arctic Ocean to locate the fallen star. But they aren't the only ones
hungry to make the new discovery-someone is trying to sabotage Tintin
and his team!
Formats:
Full-size
hardcover,
softcover
Young readers edition
Combined volume:
The Adventures of Tintin: The Crab with the Golden Claws / The Shooting Star / The Secret of the Unicorn

11. The Secret of the Unicorn
Tintin stumbles across a model ship at the Old Street Market. Only it
isn't just any model ship-it's the Unicorn, carved by one of Haddock's
ancestors, and it holds a clue to finding pirate treasure!
Formats:
Full-size
hardcover,
softcover
Young readers edition
Combined volume:
The Adventures of Tintin: The Crab with the Golden Claws / The Shooting Star / The Secret of the Unicorn

12. Red Rackham's Treasure
Tintin and Captain Haddock set sail aboard the Sirius to find the sunken
remains of the Unicorn ship and notorious pirate Red Rackham's
treasure.
Formats:
Full-size
hardcover,
softcover
Young readers edition
Combined volume:
The Adventures of Tintin: Red Rackham's Treasure / The Seven Crystal Balls / Prisoners of the Sun

13. The Seven Crystal Balls
Seven explorers return from an expedition in the Andes, where they
unearthed the tomb of an Incan priest. One by one, they fall into a
coma. Can Tintin figure out what is causing the mysterious illness?
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin: Red Rackham's Treasure / The Seven Crystal Balls / Prisoners of the Sun

14. Prisoners of the Sun
Tintin discovers that one of the last Incan descendants has kidnapped
his missing friend, Professor Calculus. Tintin and Captain Haddock
follow the kidnapper to Peru--can they save Calculus?
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin: Red Rackham's Treasure / The Seven Crystal Balls / Prisoners of the Sun

15. Land of Black Gold
Car engines have started spontaneously exploding all over the country . .
. someone's been tampering with the oil! Tintin, with Thompson and
Thompson at his side, sails on an oil tanker to the Middle East to track
down the source of the faulty oil.
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin: Land of Black Gold / Destination Moon / Explorers on the Moon

16. Destination Moon
Professor
Calculus is building a rocket, but Tintin quickly realizes that there
are spies around every corner trying to steal the professor's design!
When Professor Calculus' rocket finally takes off for the moon, Tintin
and his dog Snowy are on board.
Formats:
Full-size
hardover,
softcover Combined volume:
The Adventures of Tintin: Land of Black Gold / Destination Moon / Explorers on the Moon

17. Explorers on the Moon
Picking up where
Destination Moon left off, Professor Calculus
and Tintin discover a secret agent has managed to sneak onboard the
rocket with plans to hijack it and abandon everyone on the moon!
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin: Land of Black Gold / Destination Moon / Explorers on the Moon

18. The Calculus Affair
Tintin and Captain Haddock peek in Professor Calculus' laboratory to
find a sonic device and a very mysterious-and violent!-stranger.
Realizing that Calculus' life is in danger, Tintin and the Captain rush
to warn him before it's too late.
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin: The Calculus Affair / The Red Sea Sharks / Tintin in Tibet

19. The Red Sea Sharks
When his old friend Mohammed Ben Kalish Ezab is overthrown by Sheikh Bab
El Ehr, Tintin goes to his aid. But before Tintin can help return his
friend to power, he will have to survive shipwrecks, fires, and worst of
all, Abdullah, the emir's rotten son.
Formats:
Fullsize
hardcover,
softcover
Combined volume:
The Adventures of Tintin: The Calculus Affair / The Red Sea Sharks / Tintin in Tibet

20. Tintin in Tibet
One day Tintin reads about a plane crash in the Himalayas. When he
discovers that his friend, Chang, was on board. Tintin travels to the
crash site in hopes of a rescue.
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin: The Calculus Affair / The Red Sea Sharks / Tintin in Tibet

21. The Castafiore Emerald
When Tintin and Captain Haddock happen across a community of gypsies
they invite them home . . . just as Bianca Castafiore, the famous opera
singer, decides to visit Tintin. It's chaos at Marlinspike Hall, and
then a precious emerald goes missing!
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin: The Castafiore Emerald / Flight 714 / Tintin and the Picaros

22. Flight 714
On their way to Sydney, Tintin and Captain Haddock run into an old
friend, a pilot who offers them a ride on a private jet. But when the
plane gets hijacked, Tintin and the Captain find themselves prisoners on
a deserted volcanic island!
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin: The Castafiore Emerald / Flight 714 / Tintin and the Picaros

23. Tintin and the Picaros
Bianca Castafiore, Thomson and Thompson are being imprisoned for
allegedly attempting to overthrow General Tapioca's dictatorship.
Tintin, Professor Calculus, and Captain Haddock set out to clear their
friends' names.
Formats:
Full-size
hardcover,
softcover
Combined volume:
The Adventures of Tintin: The Castafiore Emerald / Flight 714 / Tintin and the Picaros

24. Tintin and Alph-Art (unfinished work)
The unfinished final adventure of Tintin featuring Herge's
black-and-white sketches. Opera singer Bianca Castafiore has a guru:
Endaddine Akass is handing his advice out to everyone, but Tintin
doesn't buy it-especially when he realizes that Akass might be connected
to the death of the owner of an art gallery, who had been on his way to
see Tintin when he died.
Formats:
Full-size
hardcover,
softcover