For the people that are new to Ratchet & Clank, here you can find everything you have to know!
Introduction: Ratchet & Clank is owned by Sony. The games are developed by Insomniac Games, a very great developer company! There are 2 games created by Impact Games, the 2 games where made for the PSP®. The series started in 2002 and the next upcoming game is Ratchet & Clank: Into the Nexus and simply named Nexus in PAL regions. Now let's start the tour 
Ratchet & Clank
Ratchet & Clank was released on November 4, 2002 in North America and Europe on the PlayStation 2. In the game, Chairman Drek plans to take pieces of different planets across the Solana Galaxy and create one planet for his people, the Blarg. Aside from the two protagonists, the game also introduces Captain Qwark.
Ratchet & Clank: Going Commando
The sequel, Ratchet & Clank: Going Commando (Ratchet & Clank: Locked and Loaded or Ratchet & Clank 2 in the UK and Europe), was released on November 11, 2003 in North America on the PlayStation 2. The game features Ratchet, and later Clank, trying to stop the Protopet from being unleashed on the galaxy. A variety of improvements were added in that weapons can be upgraded and Ratchet's spaceship can be modified. Going Commando also introduced strafing to gameplay. The game takes place in a different setting than the first game, this time in the Bogon Galaxy. Ratchet's personality is drastically different in Ratchet & Clank: Going Commando, with Insomniac Games deciding to make him a more caring character.
Ratchet & Clank: Up Your Arsenal
The third game in the series, Ratchet & Clank: Up Your Arsenal (Ratchet & Clank 3 in the UK and Europe) was released on November 2, 2004 in North America on the PlayStation 2. The game improves on Ratchet & Clank: Going Commando by adding more weapons and upgrades. In Up Your Arsenal, Ratchet and Clank take on Dr. Nefarious in his plan to turn all of the Solana Galaxy population into robots.
Ratchet & Clank: Up Your Arsenal is also the first game in the series to offer multiplayer - an offline splitscreen and online competitive mode.
Ratchet: Deadlocked
Released on October 25, 2005 for the PlayStation 2, Ratchet: Deadlocked (Ratchet: Gladiator in the UK and Europe) features Ratchet and Clank being captured and forced to compete in an underground sport called "DreadZone" in a remote section of the Solana Galaxy known as the Shadow Sector. The show is run by the media mogul Gleeman Vox. Ratchet: Deadlocked supports online play and a cooperative mode. In Ratchet: Deadlocked Clank is reduced to an unplayable, supporting character reflected in the game's title.
Ratchet & Clank: Going Mobile
Ratchet & Clank: Going Mobile was released in November 2005 only for mobile phones. A 2D platformer, it was developed by Handheld Games. Ratchet & Clank are transported into your mobile phone and have to fight their way back out. There are seven weapons available, and twelve levels (including an Arena). Finally, they have to defeat Maxmillian, Secret Agent Clank's nemesis.
Ratchet & Clank: Size Matters
Ratchet & Clank: Size Matters was ported to the PlayStation 2 after initial release on the PlayStation Portable and developed by High Impact Games. Ratchet and Clank are having a well-earned vacation on Pokitaru when a little girl named Luna is kidnapped and the duo are lured into a scheme plotted out by an ancient race of Technomites.
Secret Agent Clank
Secret Agent Clank, created by High Impact Games for the PlayStation Portable and later ported onto PlayStation 2, is the first game focused on Clank who goes on a mission to rescue Ratchet after he is found guilty for a crime he didn't commit. It is then up to Clank to prove his innocence.
Ratchet & Clank: Tools of Destruction
Ratchet & Clank Future: Tools of Destruction is the first Ratchet & Clank game for the PlayStation 3 and was released October 23, 2007. Developed once again by Insomniac Games it is also the first game to be set in the Polaris Galaxy. Ratchet learns about the Lombax Secret, and that he is the only Lombax that remains in the universe. Meanwhile, Emperor Percival Tachyon tries to bring back the Cragmites from exile, which involves finding the Lombax Secret.
Ratchet & Clank: Quest for Booty
Ratchet & Clank Future: Quest for Booty is the first game to be downloadable from the PlayStation Network, in Europe it was also released on Blu-ray disc as well - both for the PlayStation 3. Taking place after Tools of Destruction. It sees Ratchet trying to track down Clank with the help of Talwyn. It was released on the PlayStation Network on August 21, 2008.
Ratchet & Clank: A Crack in Time
Ratchet & Clank Future: A Crack in Time is the final game in the Ratchet & Clank Future saga. It was released for the PlayStation 3 on October 27, 2009. The game takes place after the events of Quest for Booty and focuses on Dr. Nefarious returning with another master plan. Ratchet and Clank are still separated, but nevertheless co-operate remotely. Ratchet meets another Lombax named Alister Azimuth on his journey who serves as a mentor.
Ratchet & Clank: All 4 One
Ratchet & Clank: All 4 One includes co-operative multiplayer and it allows up to four players to play as either Ratchet, Clank, Qwark and Nefarious. After Nefarious' evil plan backfires and the four are trapped in the Creature Collector, they have to co-operate to get back home.
The Ratchet & Clank Collection
The Ratchet & Clank Collection is a collection of Ratchet & Clank, Going Commando and Up Your Arsenal re-released in high definition as part of the 10th Anniversary celebrations of Ratchet & Clank in 2012. It features trophy support for all three games separately as well as online multiplayer for Up Your Arsenal. All three re-releases were also made available for individual download through the PlayStation Store.
Ratchet & Clank: Full Frontal Assault
Ratchet & Clank: Full Frontal Assault was released as part of the 10th Anniversary celebrations of Ratchet & Clank in 2012. It is a smaller game released for the PlayStation 3 and PlayStation Vita that features the duo in a downloadable adventure (also on Blu-ray in Europe) that can be experienced in single player or with friends through online and offline co-op and online competitive multiplayer.
Ratchet & Clank: Into the Nexus
Ratchet & Clank: Into the Nexus was announced on the 10th of July, 2013. The game is a "traditional" Ratchet & Clank experience similar to A Crack in Time, the last game to abide the typical Ratchet and Clank gameplay structure. It is scheduled to be released in late 2013 for the PlayStation 3.
Well… That's almost all you have to know! There is also a comic form Ratchet & Clank, Manga, Two series action figures…
If you want to know more about the games, go check out the Ratchet & Clank Wiki!
For all the stuff and merchandising from R&C, go check out RatchetMerch! You can find the games, comics, figures, RARE stuff, …